Devoted to Terror

‘May the world​ at least behold a drop, a fraction of this tragic world in which we lived,’ Salmen Gradowski wrote in a letter dated 6 September 1944, which he buried in a flask found near the crematoria of Auschwitz-Birkenau after its liberation. His words supply the epigram for Nikolaus Wachsmann’s history of the concentration camps, KL – the Nazi abbreviation of Konzentrationslager. Wachsmann’s book is a world-making history: from the close observations of individual lives and moments, and of historical forces great and small, his subject emerges. It is no ordinary world. ‘There are times when history is let off the leash,’ the Polish academic Jan Kott remembered one of his teachers saying of the war years. Wachsmann understands this.

No criminal operation has left as much evidence, great mountains of it, as the concentration camps. Wachsmann has consulted 45 archives and thousands of other sources. Enigma decoded SS radio transmissions that gave details of prisoner movements from camp to camp. SS doctors issued hundreds of thousands of death certificates for registered prisoners even after the anonymous mass murder of Jews had begun. Some of these are unreflectively revealing. Early in the war 39-year-old Josef Gaschler from Munich protested when he saw guards in Sachsenhausen punching new arrivals. He was beaten to death. He died, the certificate reads, from ‘insanity and raving madness’. Others were meant to be jokes. Among the 150,000 registered prisoners who died in 1942-43 in Auschwitz was a three-year-old boy. The cause of his death: ‘old age’.

We have the testimony, much of it contemporaneous, of tens of thousands of witnesses: Edgar Kupfer, vegetarian and pacifist, left six linear feet of the secret diary he kept at Dachau between 1942 and 1945 to the University of Chicago (the text was published in German in 1997). Fritz Solmitz, a Jewish Social Democratic journalist, wrote about the beatings and torture that would eventually kill him in September 1933 on cigarette papers that he hid in his watch.

And of course there are manifests and memoranda and directives that map in the minutest detail the workings of a gigantic system devoted to terror, slave labour and death, each a synecdoche for the bureaucratic ambitions, if not always the success, of the Nazis. Secret statistics showed a drop in the mortality rate of registered prisoners – i.e. those not gassed on arrival – in Auschwitz from 19.1 to 13.2 per cent, as a result of efforts by the Germans, there as in all the other camps, to maintain the slave labour supply. Roll calls in every camp and sub-camp allowed the Germans to keep track of the prison population on any given day. Prisoners were often on the move and this too was carefully documented. Wachsmann recounts the experiences of Moritz Choinowski, a Pole who lived in Magdeburg. Arrested in September 1939 and sent to Buchenwald, he was classified as a political Jew, so wore a red and yellow star. From Buchenwald he was sent to Auschwitz on a freight car with four hundred other men; he survived his initial selection, and then two further selections. He survived the death march back to the west when Auschwitz was abandoned; he survived the freezing cattle cars that took him first to Gross-Rosen and then to Dachau. In one of those explosive tiny details that would seem too crazy in fiction, we are told that he was treated for an ear infection in the infirmary at Dachau a few weeks before the liberation.

Most prisoners survived only one or two journeys, all of them documented. The level of detail we have is astonishing. My maternal grandfather, Max Weinberg, was sent to Theresienstadt in Bohemia from Frankfurt am Main on 15 May 1942, two weeks before his 73rd birthday, on Transport XII/3, Train Da 515. He was prisoner 1307. He must have been one of the few Jews left in Germany. Two and a half years later, on 23 October 1944, as prisoner 1034, he was transported from Theresienstadt to Auschwitz-Birkenau. This was two weeks after an abortive Sonderkommando rebellion had blown up one of the crematoria there and a week before the last mass gassing. The Sonderkommandos were Jewish prisoners who were forced to help dispose of the bodies of those killed in the gas chambers. Gradowski was one of the Sonderkommandos killed in the rebellion. All of this is history from below, the story of the camps recreated from countless telling details given by those who suffered and those who imposed the suffering.

But Wachsmann also works from above. The KL were in a sense the quintessential National Socialist institution. The Nazis were adept at responding to the ever changing needs of the state: instrumental political terror, social cleansing, genocide, slave labour, medical experimentation and more. This is the first book to try to give a comprehensive account of the camp system in its entirety. Wachsmann disentangles the history of the KL from the related but distinct history with which it is often conflated: that of the Holocaust, and more specifically of Auschwitz, among all 27 major camps the one that has, in the world’s imagination, come to represent the Holocaust. Because of the camp’s size and the number murdered there, Auschwitz seems to overshadow all the other camps. It also captures our attention because we know a great deal about it. Its machinery of death remained largely intact for its Soviet liberators to study and photograph. It was the only death camp (Auschwitz II) that was also a large slave labour camp (Auschwitz I), with the result that tens of thousands of slave labourers, having endured selections, random violence and the death marches, survived to bear witness to genocide. Finally, Auschwitz has a special place in the world’s memorial culture: 27 January, the date the camp was liberated by the Soviet army in 1945, was designated in 2005 by the United Nations and the European Union as International Holocaust Commemoration Day. So today the history of the KL and the history of the Holocaust have merged in the name of Auschwitz, which stands for both.

This will not do. Most of those killed in the Holocaust were not inmates in concentration camps. By the time the gas chambers of Auschwitz were put to use in the spring of 1942, more than a million Jews had been shot by paramilitary death squads and buried in ditches (tens of thousands of non-Jews met the same fate). Beginning in early December 1941, the death camp at Chelmno gassed or shot 150,000 Jews who lived in the parts of Poland incorporated into the Reich. The great majority of those who lived in the so-called General Government were murdered in 1942 and the first half of 1943 at Belzec, Sobibor and Treblinka. These were the extermination camps of Operation Reinhard, named after SS General Reinhard Heydrich, who convened the Wannsee Conference in January 1942 to organise the Final Solution. (Heydrich was ‘martyred’ by partisans in Prague in June that year; 1300 Czechs were gassed, burned alive or shot in revenge.)

Much of what we have come to see as the particular moral debasement of the concentration camps was absent in the death camps. There were few selections: almost everyone who arrived had been selected for murder in the ghettoes from which they came. There were no Muselmänner, the exhausted, hollowed out camp inmates who have come to represent the evil of the KL, the stripping of humanity from human life. There was no camp hierarchy; no classificatory system marked by badges; no camp orchestra; no struggle for survival; no medical experimentation: 99 per cent of those who entered the death camps were dead within 24 hours.

My Tante Toni, my father’s eldest sister, a healthy dentist three months short of her 44th birthday, might well have been selected for labour at a concentration camp. She passed through the extermination camp of Sobibor in a single day: 9 July 1943. These camps were grotesquely efficient: Sobibor murdered about a quarter of a million people, a quarter as many as Auschwitz-Birkenau in one three-hundredth of the space and half the time. Precisely because of this efficiency, we know relatively little about the dead. There are only three survivors’ accounts from Belzec, where, between 17 March and late December 1942, 434,500 Jews were murdered. As Primo Levi said, we know little of those who were truly at the bottom.

Conversely, much of the story of the concentration camps does not overlap with that of the Holocaust. The camp system was a latecomer to the project of genocide. There was no representative of the KL at the Wannsee Conference. It was only after the conference that Himmler decided the camps could play a big role, not primarily as sites of immediate extermination but as reservoirs of Jewish slave labour. Only towards the end of the war, as Wachsmann points out, did the majority of Jews find themselves in camps and only for a few weeks in 1938 were they the majority of registered inmates. (Most Jews sent to the two concentration camps that were also death camps – Auschwitz II and Majdanek – were murdered on arrival.)

One way to think of this distinction between the history of the KL and that of the Holocaust is to shift our mental focus from Auschwitz to Dachau, the earliest of the major camps, the one that was always nearest the heart of Himmler and his comrades, and the one that was for a long time after the war the best known to the general public. Eisenhower ordered that as many American soldiers as possible be taken to see its gas chamber and crematorium. (In fact the gas chamber probably wasn’t used very much; those selected as too weak to work were sent elsewhere to be killed.) The familiar pictures of heaps of dead bodies in front of a crematorium were taken there; canonical horrors – thirty railway cars of dead and decomposing bodies – were found by Allied troops as they approached the camp; the judges at the Nuremberg Trials were shown a film made there after its liberation. Opened in March 1933 to house political prisoners, it was seven years old when Auschwitz was founded.

Yet a recent poll of Germans found that Auschwitz was by far the most recognised KL and was known by the vast majority only as a place where Jews were murdered. Of course it is true that 870,000 Jews were killed there. But historical amnesia matters, both because it denies others their history but also because it erases vast dimensions of Nazi crime. Fewer than 10 per cent of those polled could name any other category of victim – communist, homosexual, gypsy, ‘asocial’, Soviet or Pole. And in some ways it is hard to blame them for their ignorance. The first memoir by a criminal KL inmate – a ‘green triangle’ – was published in 2014. We know very little about the Soviet victims, although they were the first to be subjected to the various techniques of mass murder that the KL perfected. Hundreds of thousands of them were killed in concentration camps. (The death by systematic starvation and maltreatment of three million Soviet POWs is usually considered separately.)

Auschwitz I, the Stammlager or main camp, opened in June 1940 as a place for Polish political prisoners; the first mass deportation of Jews did not arrive there until late March 1942. It was deadly from the start. With characteristic precision, SS bureaucrats noted that the corpses of 2915 prisoners were taken from the main camp to Crematorium I between 7 October and December 1941; of the 147,000 Poles sent to Auschwitz, 74,000 died, more than the total number of prisoners, Jews and non-Jews, to die in any other single KL, with the exception of Mauthausen and possibly Majdanek. This isn’t to detract from the fact that Jews were the sole category of the subhuman targeted for complete annihilation.

When the Allies liberated the concentration camps in the west and the Soviets the ones in the east, they saw a great deal more than evidence of what we call the Holocaust. ‘Holocaust, Jewish, 1939-1945’ didn’t become a Library of Congress subject heading until 1968, when it replaced ‘World War II, 1939-45 – Personal narratives, Jewish’. It became a commonplace, without the modifier, only in the 1970s. The Israeli National Library omits ‘Jewish’ as a modifier and pushes the date back to 1933. The Polish Library classifies material on the subject under ‘Martyrology, Jewish’. The reasons behind the various classificatory schema are not hard to understand. But political differences, even anti-Semitism, cannot explain the way the camps were first understood and represented to the public at the end of the war. What the liberators found in the concentration camps and sub-camps were tens of thousands of frozen bodies and starving inmates; abandoned ghost trains that the Germans had, in one last apocalyptic effort to preserve its supply of slave labour, packed and sent off to nowhere. The gas chambers and crematoria that the Allies discovered had been used not for the Final Solution but to kill those no longer fit to work and burn their remains. The survivors – 155,000 in the main camps, another 90,000 in satellite camps – were hungry and sick. Ten per cent died within weeks. Typhus raged among the 53,000 liberated at Bergen-Belsen. My cousin Renata Laqueur, who was liberated while on a train headed perhaps to Theresienstadt, survived the louse-borne disease; her sister did not (Wachsmann quotes several times from her diary). The liberators, in short, found unspeakable human misery but in those early months no one seems to have recorded precisely who these humans were. We know in some cases. Of the 8,646 people US troops found in the main camp at Dachau on 29 April 1945, half were Soviets, a third Jews, the rest Germans; on 26 April, the last day for which we have German records, there were 67,665 registered prisoners in the main camp and all the sub-camps at Dachau, of which 22,100 were listed as Jews and the rest as political prisoners. In Buchenwald there were 5000 Frenchmen, 3500 Poles and Polish Jews, 2000 Russians, 2000 Czechs, 2000 Ukrainians and 2000 of other nationalities. But the issue here goes well beyond questions of sociology, or national and ethnic identity.

Eugen Kogon, a conservative Catholic journalist who, after a flirtation with the Nazis, fell foul of the regime, was sent to Buchenwald, survived and wrote the first book that tried to give an overview of the concentration camps as a system, makes this clear. The Theory and Practice of Hell was published in German in 1946 with a print run in the first year of 135,000; it was translated into English in 1950. Kogon is unambiguous about the status of Jews in the Nazi hierarchy of murder. ‘The chief victims of Auschwitz were Jews from all the countries of Europe,’ he writes. ‘It is impossible to present here anything like an exhaustive picture of the Jewish mass tragedy.’ Readers would have to be content with a brief account of the fate ‘that engulfed [the Jews] in the concentration camps proper, as well as in the eastern ghettoes’. The subject of his book, however, is not the fate of Europe’s Jews, but institutional inhumanity on an unprecedented scale.

For the first twenty years after the story of the concentration camps came to be known, the isomorphism of Auschwitz and the Holocaust was not the commonplace it has become today. In the immediate postwar period there was no prototypical prisoner. On the cover of the cheap American edition of Kogon’s book is a photograph of a dead body slumped on a fence; it resembles the drawing of a body sprawled in the dirt on the original cover of Primo Levi’s If This Is a Man, first published in 1947. The cover of the 1950 Secker and Warburg edition shows prisoners wearing red triangles behind a barbed wire fence with a smoke-belching furnace in the background. Kogon’s book was received in the context of a humanistic universalism. The concentration camps, Reinhold Niebuhr wrote in his review, were ‘the closest thing to hell in human history’; ‘the moral sloth and inhumanity’ Kogon’s book reveals, he added, proves ‘that it is possible for mankind to fall to a lower level than anyone would have supposed in recent centuries’.

Wachsmann has no interest in reviving this high-flown rhetoric, or in the metaphysical and political claims that have been made about the nature of Nazi crimes, or in adjudicating between a general or a Jewish-centred interpretation. Must we choose? Saul Friedländer’s two-volume history of Nazi Germany and the Jews, published between 1997 and 2007, is a brilliant and comprehensive account of what we now call the Holocaust. It is a model for Wachsmann’s magisterial history of the concentration camps.

Soon after​ Hitler came to power in January 1933, tens of thousands of people, mainly communists and socialists, were taken into ‘protective custody’ as enemies of the state by a variety of party and state organisations. By the end of the year 200,000 had been held. This was made possible by the emergency decree suspending civil liberties that Hitler pressed President Hindenberg to pass the day after the Reichstag fire on 27 February. About 5 per cent of those arrested were Jews. This number was high – Jews made up about 0.75 per cent of the population – but was probably an accurate enough representation of their presence on the communist and social democratic left. (It’s difficult to say for sure. We know that 2 per cent of Reichstag deputies during the Weimar Republic listed their religion as Jewish but all Communist Party members and many from the social democratic parties refused on principle to give their religion.) But Nazi anti-Semitism was already evident: Jews were far more likely than others to fall victim to random violence.

It was by no means clear that a vast system of camps would emerge from these beginnings. Hermann Göring thought the Ministry of the Interior could deal with enemies of the state through the already existing system of courts and prisons. And the early camps were hard to manage. The army had to intervene when SS members went on the rampage in a camp in Emsland near the Dutch border, furious at the release of some prisoners. But Himmler, head of the Munich police as well as the senior officer in the SS, saw that the KL could be used as a permanent instrument of terror. On 22 March 1933, the first concentration camp proper opened in an old munitions factory 21 km north of Munich. Dachau would, Himmler hoped, hold five thousand people. He was dreaming small.

In part this was because concentration camps, or at least a permanent system of such camps, had few precedents. The British concentration camps in South Africa – the term was first used during the Boer War – were very different from what the Nazi camps became. There were no arbitrary killings, no culture of systematic terror, no cadre of ideologically driven guards. Deaths in the Boer War camps were caused almost entirely by the spread of epidemic diseases like measles in a young population that had not been exposed to various pathogens. It is in no way to absolve the British to point out these differences from the German camps. The gulags are nearer relatives: in 1942-43 their annual mortality rate was around 25 per cent, but even that is less than half the rate in the KL. The closest comparison is with the prison system that emerged in Germany and elsewhere in the 19th century. Wachsmann here draws on his earlier book, Hitler’s Prisons: Legal Terror in Nazi Germany (2004), to describe how German prisons and concentration camps both had rigid schedules, roll calls and harsh living conditions and made use of special detention and forced labour. I think he could go further. More disturbing is the shared assumption of prison wardens and concentration camp commanders that violence against supposedly lesser people (criminals or Jews) didn’t count, even if it wasn’t legally sanctioned. In the American South after the Civil War black convict labourers, leased out for dangerous, back-breaking work and subject to summary punishment and execution, sometimes had a mortality rate as high as 50 per cent in certain states. These are concentration camp levels. Mortality among the tiny minority of white prisoners was around 2 per cent. Even when things improved for black convicts in the 1880s the annual mortality rate was still 15 per cent. The absolute power of guards and wardens over the lives of those behind walls, Wachsmann helps remind us, has a long history. But never before had so many human beings been subject to extra-legal terror as in the Nazi concentration camps.

By 1935 the number of detainees in camps had shrunk to four thousand, compared to the hundred thousand held in regular prisons. Hitler issued a general amnesty in August that year. Many in the Nazi hierarchy, especially in the Ministry of the Interior, disliked the random and unregulated violence of the camps and would have been happy to see them closed down. But Himmler had discovered in Theodor Eicke a man who could help him create an empire of terror. On 2 June 1933 Himmler had Eicke released from the insane asylum where he had been sent, having fallen out with his SS superiors, and made him commandant of Dachau. Eicke, who called himself a ‘political soldier’, set out to build a corps of young guards. They were ordered to watch floggings in order to help harden them and encouraged to behave as violently as they wished. He developed a homoerotic camp culture rooted in brutality. It was under Eicke that Rudolf Höss, the future commandant of Auschwitz, first aspired ‘to become notorious for being hard so that I would not be considered soft’. Eicke proclaimed that his men were dearer to him than his wife and children.

Eicke’s career, and in a way the future of the KL, was made by the series of murders known as the Night of the Long Knives, from 30 June to 2 July 1934, the fratricidal killings that broke the power of the SA, which was essentially replaced by the SS. At 6 p.m. on 1 July 1934 Eicke opened the door to the cell where Ernst Röhm, the head of the SA, was being held (he had been arrested by Hitler the previous day) and shot him at close range. Röhm’s brownshirts were taken to Dachau and murdered; more men died there in the next three days than had been killed in the camp in the previous year. Over the next three years the concentration camps went from a precarious existence to being a key part of the Nazi regime.

Three​ things made the camp system possible. First, unlike prisons, the camps were increasingly able to operate outside the legal system. When some jurists objected to the imprisonment of so-called ‘asocial elements’, Himmler argued that it might not follow the law but followed National Socialist sentiment. Prisoners in protective custody were not entitled to lawyers. Those who had come to the end of their prison terms could be sent to KLs for protective custody and ‘rehabilitation’ without the need for a new trial or judicial involvement. Step by step, an increasingly autonomous regime of terror was emerging.

In May 1938 the courts allowed the first execution – as distinct from the many extra-legal murders – in a concentration camp. Nine months later, on 8 September 1939, a prisoner was executed without even the pretence of judicial permission. There would be thousands of such executions over the next six years; some were quiet affairs like that of Johann Heinen, the first victim; other were theatrical displays of absolute power. These were relatively rare: a prisoner on the gallows in front of a crowd might disrupt the theatre and become human again. Primo Levi records one man’s last words of defiance: ‘Kameraden, ich bin der Letzte’ (‘Comrades, I am the last one’).

Second, the concentration camps, unlike German (though not American) prisons of the time, were an economic resource, a reservoir of slave labour. To make good on this, Himmler had worked quickly: Sachsenhausen, the first purpose-built camp, was finished by the end of 1936; Buchenwald opened in 1937, carefully constructed around the protected oak tree under which Goethe had rested; Mauthausen and Flossenberg opened in 1938, and Ravensbrück, the only camp built especially for women, in 1939.

Third, the KL and radical anti-Semitism came to be useful to each other. Jews were more likely to die in the camps than other categories of prisoners because they suffered more intense abuse and received less help and sympathy from the general prison population. Still, in the 1930s their numbers remained small: about 5 per cent of inmates – mostly ‘race defilers’ under the Nuremberg laws, returning émigrés and political enemies of the state. Kristallnacht, the great pogrom of 9-10 November 1938, was a turning point: thirty thousand Jewish men were arrested, meaning that, for the first and only time, Jews constituted a majority of the KL population. They were very badly treated: 469 died in November and December 1938 alone. But the purpose of this round-up was not extermination or permanent confinement, it was forced emigration and extortion. The great majority of Jews were soon freed. My Uncle Otto, my mother’s brother, had his teeth knocked out, but was released when his wife managed to secure a visa for Ecuador.

By 1939 the camps had a place within the Nazi system, although their growth had stalled: they contained 21,000 prisoners in September 1939, down from 51,000 the year before. They were deadly but not yet murderous on a large scale. War would be their making. When a Polish border incursion had to be faked to provide a casus belli for German invasion the camps provided the human props. Inmates were drugged and driven in black Mercedes to where the attack was to be staged. They were dressed in Polish uniforms, then shot and beaten so that their faces were unrecognisable, before being photographed as evidence that an attack had been thwarted. They were, as Wachsmann says, the first of 1.7 million KL prisoners to die in the war.

When war began, the camps had a new role: the subjugation of Germany’s defeated enemies. Auschwitz opened on 14 June 1940 and housed 700 Poles. By early 1942 it was the largest camp, with 12,000 inmates, three-quarters of them Poles. In revenge for purported atrocities carried out by Poles against Germans, 110 Poles were forced into a small enclosure made of wood and barbed wire at Buchenwald and starved. Two survived. ‘And yet,’ as Wachsmann writes, ‘even during the worst days victims were still counted in their dozens, not hundreds or thousands.’ A shift in the scale of terror took place in 1941 as a consequence both of forces within the camps and of the new demands and opportunities offered by the conquest of eastern Poland and the invasion of the Soviet Union.

The major problem in the camps as they expanded was the increasing number of Muselmänner, prisoners Wachsmann describes as ‘the living dead’, ‘exhausted, apathetic and starved’. On the one hand, the KL were committed to the exploitation of prisoners as slave labourers, and so made some effort to keep them alive. This explains what had always seemed puzzling to me, the existence of infirmaries and doctors, even in Auschwitz at the height of the Holocaust. Some prisoners were even sent out of the camps to see specialists. On the other hand, since ‘annihilation through labour’ was official policy the problem became what to do with those who could no longer work. The solution was culling: ‘selections’.

Doctors from the T-4 euthanasia programme, named after the address of its office on Tiergartenstrasse, were sent to the camps to identify those unfit to work. They had already decided that 70,273 German inmates of institutions for the mentally or physically handicapped were unworthy of life and had overseen their deaths in gas chambers. In Buchenwald one doctor admitted that he tended to select Jews: 45 per cent of the 187 murdered there in July 1941 were Jews, three times their proportion in the camp population. It is tempting to see this as foreshadowing what was to come. Yet in Gusden doctors picked mostly Spaniards and Poles; in Dachau it was Germans. About 6500 inmates died as a result of this programme. Many Muselmänner were also killed without first being selected by the doctors of the T-4 programme. Dachau became a major dumping and killing ground for the half-dead.

Outside forces were even more important in the increase in the scale of KL murder in 1941. The early successes of the Wehrmacht had brought millions of Jews and Soviet POWs under the control of the Reich. The Jews were not yet a primary concern of the concentration camps, but the five million Soviet POWs were of considerable interest to the SS. What Wachsmann calls a ‘colonial euphoria and genocidal utopianism’ swept the organisation. Himmler ordered a new camp to be built in Birkenau (near Auschwitz) and another at Majdanek; the small camp at Stutthof near Danzig was greatly expanded to house what was expected to be an endless supply of slave labour. Himmler hoped for a quick tripling of the KL population.

His dreams weren’t fulfilled. If you were a management consultant you’d say that head office wasn’t clear about its strategy. ‘So have these people come here to die or to work?’ a middle manager at Sachsenhausen asked. ‘Must we choose?’ Himmler would have replied. But he had miscalculated. Annihilation through labour was only possible if the supply of labour was limitless. But the Wehrmacht had starved to death too many Soviet POWs and with the war in the east stalling there were not enough replacements. Hitler ordered that some prisoners be used as slave labour in camps outside SS control. And the KL as a system found it hard to calibrate levels of brutality; in one camp only 89 prisoners out of 25,000 survived after three months.

The camps were busy trying out different methods of mass murder. Sachsenhausen developed the killing booth, an innovation that attracted Theodor Eicke to an early demonstration. Selected POWs were told that they would be measured as part of a medical exam; they entered a soundproof booth and sat on a bench with their backs to the wall; soothing music was piped in; then through a small hole behind them a guard fired a single bullet. The killer did not have to see or hear his victims and prisoners cleaned up the brains, bone and blood. This method could kill more than three hundred POWs a day. Flossenberg and Gross-Rosen used lethal injections, a technique perfected on Muselmänner. Dachau just shot them in a field – more than four thousand POWs died this way between September 1941 and June 1942. In the east a new and more promising technique was in development: the purpose-built gas chamber. On 5 September 1941 hundreds of Soviet POWs were forced into a cellar at Auschwitz and Zyklon B crystals tossed in. They died a grotesque death. There were technical problems: bad ventilation made it hard to clean the gas chamber quickly for the next round; bodies had to be dragged through the whole camp to reach the crematorium. Purpose-built gas chambers were constructed near new crematoria. Himmler, an agronomist by training, was especially happy with a new machine that could crush bone to a size that could be used to fertilise the fields of what he hoped would be a vast new agricultural area around Auschwitz. By the end of 1941 these innovations had spread to other camps, although it was never possible entirely to replace the older methods or to eliminate the personal engagement of killers with their victims that the gas chambers were meant to minimise.

Chapter 6 of Wachsmann’s book, ‘Holocaust’, stands at its absolute centre: 288 pages come before and 288 pages after. In 1942, he writes, ‘the Holocaust transformed the concentration camp system.’ Two great Nazi crimes began to share a common history. But what we often think of as the almost fatalistically inevitable confluence of Jewish extermination and the concentration camps turns out instead to be strangely contingent. Himmler had long wanted the KL to play a bigger role in the Nazi economy. In March 1942 he placed the camps under the control of the WVHA, the business and administrative unit of the SS, which now managed them, arranged the distribution of slave labour, and organised the theft of the property of those murdered. Anyone interested in the scale of this enterprise should have a look at the size of the WVHA’s headquarters, at 125-135 Unter den Eichen in Berlin.

In February 1942, after the Wannsee Conference, Himmler had suggested to the Führer that Jews should be rounded up in order to replace the diminishing flow of Soviet prisoners. Hitler ranted, Wachsmann writes, about ‘the need to make Europe free of Jews’. There was, he said, no reason to ‘look at a Jew with different eyes than a Russian prisoner’. Himmler called Heydrich, the operational head of the Final Solution, in Prague; the note about the call in Himmler’s office diary reads: ‘Jews into the KL.’ Four new camps were built in the east to house Jewish slave labourers; mass deportations to Auschwitz began. The commandants were reminded that the new arrivals were not to be killed on arrival but exploited as workers.

Precisely how the emphasis shifted to genocide within the KL is still unclear; key documents are lost. At first only about 10 per cent were murdered on arrival in the camps. Adolf Eichmann, who was in charge of managing the deportations of Europe’s Jews to the KL, was on familiar terms with Rudolf Höss, the Auschwitz commandant, and visited the camp to encourage him to increase the murder rate. Within months Höss settled on a new ratio: 80 per cent to the gas chambers and 20 per cent to forced labour. Further selections kept disease at bay by sending the sick who had survived the initial round to be gassed.

Himmler flew to Auschwitz for a grand inspection of all camp operations on 17 July 1942. He encouraged the staff to devote itself to murder and economic exploitation; he watched a woman being flogged; he watched a recent transport of Jews being gassed. The full story of this part of his visit is even ghastlier than Wachsmann describes if we believe the account of Rudolph Vrba, a Slovakian Jew who escaped from Auschwitz in 1944 and was the first to tell the world of its horrors. Himmler was supposed to arrive at 9 a.m. By 8.45 the new gas chamber, disguised as a shower, was packed full of three thousand Polish Jews. Guards wearing gas masks stood on the roof. No Himmler. He had not finished breakfast; messages went back and forth; screams and pounding from inside; the guards outside were increasingly edgy. Finally at 11 a.m. Himmler appeared. The process was explained to him; the pellet was dropped. Later the bodies were removed by Sonderkommandos, gold teeth extracted, and the corpses sent to the crematorium. Guests at a celebratory dinner that night had never seen Himmler so light-hearted.

Between the beginning of 1943 and the end of 1944 Auschwitz became the flagship of the system: a death camp linked to a concentration camp. In the spring and summer of 1944 it was working at full capacity to destroy Hungarian Jewry – a new pool available for labour or murder. As Wachsmann writes, by this time ‘most European Jews under German control had long since been killed.’ At the same time, the SS main office was trying to figure out ways to moderate the mortality rate among Jews and others selected for slave labour.

Seven thousand Germans were employed at Auschwitz. The housing for staff was ‘opulent’, according to Wachsmann; thousands of nobodies lived like aristocrats. After the war, the widow of the notoriously sadistic commandant of the nearby camp at Plaszow regretted only that the ‘beautiful time’ had come to an end.

Plunder was part of the business plan. A secret report estimated that 90 lbs of gold were extracted from the teeth of gassed prisoners, mostly Jews, in the last two weeks of May 1944 alone. Where there was so much money to be made, there was also massive corruption. A customs official caught one camp guard trying to smuggle out a fist-sized ball of gold. There were flourishing black markets in the camps themselves, run by guards and privileged prisoners. At the top the spoils were considerable. Karl Otto Koch, commandant first of Majdanek and then Buchenwald, stole on the scale of a major drug lord. He was executed by an SS firing squad just before the war ended. In keeping with the KL’s macho ethos, he refused a blindfold.

The needs​ of German industry in late 1943 and 1944 changed the KL as much as the Holocaust had in early 1942. Hundreds of new satellite camps were created to provide slave labour for war industries. (The exact number depends on how one counts them: Wachsmann estimates there were 560; a survey in 1990 based on an earlier report by the Allies has a much higher figure and runs to nearly 700 pages of small type.) Revenues soared: in 1943 the KL took 200 million RM; in 1944, 500 million. So did camp population: 315,000 in December 1943, 524,286 in August 1944, 706,650 in January 1945. The zenith of the system coincided with its collapse and the death of almost half of its prisoners.

They died in many ways. Some were worked to death. More people, it is said, died in underground caverns building V2 missiles than were killed as a result of their use against Allied cities. Those too sick to work, if not shot on site, were sent to Auschwitz and Mauthausen to be gassed. Many died on the forced marches of 1944 and 1945 from abandoned camps in the east back towards Germany. Leaving able-bodied slaves behind would have been unthinkable from the WVHA’s perspective; those no longer able to move were shot en route. Thousands died from disease in so-called quarantine compounds within each major camp: 18,168 in one month at Bergen-Belsen – including Anne Frank – out of a population of around 45,000. In one last spasm the SS killed more Jews and high-value prisoners: foreign agents and German opponents of the regime like the theologian Dietrich Bonhoeffer. Some prisoners murdered one another out of the desperation of hunger. Seven thousand former inmates died as a result of friendly fire in ships in Neustadt being bombed by the Allies, the worst naval disaster in history (2388 died in the Japanese attack on Pearl Harbor).

Death in the KL after the liberation of Auschwitz was no longer driven primarily by racial ideology. Gender played a big role: Jewish women had a higher survival rate than non-Jewish men in the satellite camps. So did nationality. In the huge sub-camps of Dora and Ellrich, Belgian and French prisoners were more likely to die than Jews, gypsies or Russians. In the death marches from the east it was the weakest physically who perished.

When we think of the grotesque medical experimentation that took place in concentration camps we tend to think of Mengele at Auschwitz and treat his crimes too as part of the Holocaust. But, like the history of concentration camps generally, the crimes of Nazi doctors have their own history that follows from the superordinate notion that there are humans who are subhumans, and therefore do not need to be treated as humans are. Of course Mengele availed himself of the Jewish ‘material’, as did other colleagues tempted east by research possibilities. The Reich University of Strasbourg needed skeletons from all over the globe for its research and so a special commission came to Auschwitz to pick prisoners from as many nationalities as it could find to be murdered for science. Some Jewish prisoners were sent west to test gas chambers or to collect body parts for the Anatomical Institute. The Allies found vats of these when they liberated the Natzweiler camp in Alsace. There were few Jews in the old camps after late 1942, so doctors experimented on Poles and Soviets instead. Some of the doctors were idiots; one asked the prisoners to help him write his thesis. Some were fraudulent, like Sigmund Rascher, who got his job in Dachau through Himmler and was executed in 1944 for corruption. Himmler even suggested experiments Rascher might carry out; on one occasion he asked him to test whether a man who had been submerged in icy water could be revived if he were fondled by two naked women. Polish women in Ravensbrück were used as guinea pigs for gas gangrene experiments; studies on malaria were done at Dachau mostly on Poles and criminals. A drug meant to protect soldiers from toxic phosgene was tried out in the small gas chamber at Natzweiler. Efforts to find a vaccine against typhus were tested on inmates at Buchenwald. Around twenty thousand people suffered in these studies and several thousand died.

Wachsmann deals well with many of the questions that persist in the overlapping histories of the concentration camps and the Holocaust. Why, for example, did the Allies not bomb Auschwitz and the railway leading to it and if they had would it have made any difference? It is by now uncontroversial to state that they showed no great urgency to take military action. By the time they could have acted, in July 1944, the IG Farben plant was a more important target, and it was too late anyway: most Jews were already dead. It was unlikely in any case that the gas chamber crematorium complex could have been accurately targeted; the bombs would probably have hit the prisoner compound. Railway lines are hard to hit and easy to repair; trains are easily rerouted. Finally, as this book makes clear, the Nazis showed prodigious creativity when it came to finding venues and means of murder.

On the question of what Primo Levi called the grey zone, the ‘impossible choices’ demanded by life in a morally perverted world, Wachsmann is wise and unjudgmental. He recounts stories of extraordinary kindness. Otto Wolken, a Jewish prisoner doctor from Vienna, found Luigo Ferri, an 11-year-old Italian boy, in the quarantine camp of Birkenau, where he had ended up by accident. He would have been dead within hours if Walken had not bribed a Kapo to register him, kept him off selection lists and allowed him to sleep in the infirmary. Both were alive to greet the Russian liberators.

Wachsmann tells other stories that aren’t so heartwarming. Helmut Thiemann, a communist Kapo who survived seven years in Buchenwald, wrote in a self-justificatory report to the party after the war that he had co-operated with the SS in selecting prisoners from the infirmary for murder in order to to keep his job there: ‘Because our comrades were worth more than all the others, we had to go along with the SS to a degree, in regard to the extermination of the incurably sick and invalids.’ The Sonderkommandos did their work because, as one admitted in his testimony, ‘I wanted to stay alive.’ Ordinary morality did not pertain. My cousin Renata reports in her diary that she stole food from her husband when they were in Bergen-Belsen together; she also stole food later to keep him alive after they had been liberated. She says in an interview for the Holocaust Memorial Museum in Washington DC that she kept stealing after she returned home to Amsterdam. Her husband suggested that she see a psychoanalyst to regain her moral compass in a post-camp world.

On the question of passivity in the face of murder on an industrial scale Wachsmann’s evidence is definitive. Bruno Bettelheim’s view that the Jews of Europe, and by extension the Nazis’ other victims, went to their death ‘like lemmings’ is untenable, but still worth refuting because of its persistence: ‘It was the compliance of most victims that made the Final Solution possible,’ Konrad Jarausch blithely states in his new history of Europe in the 20th century.*

Just as clueless is the idea, patiently dissected by Primo Levi, that resistance or escape was possible. Most people selected for gassing at Auschwitz did not know what was in store, or hoped against hope that what they had been told was not true. The camp SS kept up the charade as long as possible; a reassuring ambulance followed those selected to the gas chamber. Those who did know what was about to happen could cry and implore as much as they wanted as they were taken to the gas chamber or the infirmary or the killing field under heavy guard. Gypsies, Höss complained, were the hardest to herd into the gas chambers but that did not change their fate. The slightest hint of opposition was severely punished: two hundred prisoners in one sub-camp in 1944 were hanged for supposedly sabotaging production. This book, however, demonstrates that there was one form of resistance that could not be entirely suppressed: the collection of data, the writing of diaries, the taking and smuggling of photographs that document a suffering that would otherwise be unimaginable.

The title and running heads of KL are set in Prestige Elite Bold, a font that mimics that of the Olympia Robust, the field typewriter used by the Wehrmacht and the SS. It was the corporate typeface of the camps from their beginnings in March 1933 to their end in the ruins of the Third Reich. Its use helps to remind us that we are reading the history of a vast bureaucracy of terror. Repeated words remind us of particular details. Music: music played by the orchestra as slave labourers went to work; music in the ears of Soviet POWs about to be shot in the head; music – waltzes – played at Majdanek as 18,000 Jews were gunned down in a day; music – Schubert’s Rosamunde played by the camp orchestra as the trains arrived at Auschwitz. And vomit: the Polish prisoner who thought he had seen everything, but vomited as he was forced to clean up the decayed bodies of the Soviet prisoners on whom the Auschwitz gas chamber was first tested; the young German Jewish woman who vomited constantly from the smell of burning bodies; the young SS doctor who had a breakdown at his first selection, got drunk and vomited. Mengele calmed him down and he began to feel better about his work when his wife came to join him.