Exactly 81 years after the liberation of Auschwitz by Soviet troops on 27 January 1945, we are still seeking to understand the catastrophe that engulfed the Jews of occupied Europe. Amid the abundant literature on Auschwitz, If This is a Man by the Italian writer and chemist Primo Levi remains exemplary. Published in Italy in 1947, it offers a warning to those who deliver facile judgements of condemnation: only those who survived the Nazi camps have the right to forgive or condemn. Levi, a survivor, took his life in 1987. Whether the depression that defeated him was compounded by his terrible past is a matter we can only speculate about. He was 67.

The year before he died, in 1986, Levi published an essay collection on the nature of totalitarian barbarism. The Drowned and the Saved is the book where Levi’s moral obligations to the past are most thoroughly exercised, and where the hardest questions are asked. For the cover of the Italian edition, he chose a detail from Hans Memling’s medieval altarpiece The Universal Judgement, where the damned writhe and howl in a fiery hell-pit. The image conveyed the awfulness of what Levi had been writing about. His Dantesque language in The Drowned and the Saved (‘we gasped for air breathed a hundred times over’) suggests a state of vacuous horror.

The book’s most discomfiting essay, ‘The Grey Zone’, considers the concentration camp prisoners who were forced to collaborate with the authorities in order to survive. In return for clothes and extra rations, the Special Squads (Sonderkommandos) of Auschwitz were required to shepherd Jews to the gas chambers and oversee the industrial exploitation of their corpses (ashes, teeth, hair). In the essay, Levi insists that we suspend moral judgement on the Sonderkommandos, as they were flung into an infernal environment where they had to face impossible choices. In most cases, they were ordinary Jewish men degraded into abetting the Nazis in their demolition project with its assembly-line gassings. Other prisoners in the grey zone (in Italian, la zona grigia – Levi coined the term) were no less useful to the Nazi tyranny. Levi was among them. In Auschwitz, as a chemist, he was set to work in the laboratory of a synthetic-rubber factory where he received some extra food. By this forced complicity, he made a step up the ladder to privilege and entered the grey zone.

One may ask what drew Levi to the awful task of raking over and interrogating the legacy of the Sonderkommandos. It was not some quasi-religious obsession with evil (as one Catholic Italian critic suggested). The chief reason why Levi wrote ‘The Grey Zone’ was a need to understand how such morally ambiguous behaviours could have evolved at Auschwitz. The essay – a work of ethical meditation in the school of Italy’s Enlightenment writer Alessandro Manzoni – describes Auschwitz as an ant-heap of informers and opportunists who operated in an ambiguous zone where the stereotypes of brutal oppressor and oppressed victim, of ruler and ruled, had broken down. And there was another reason why Levi wrote ‘The Grey Zone’: he wanted to counter attempts made by Hollywood to recreate Hitler’s Final Solution on the screen. Tawdry box office hits from the 1970s such as The Night Porter and Salon Kitty played on simplistic master-slave fantasies of the SS and their victims. The tendency to simplify into crude binary categories of good and evil was dangerous, said Levi, because it reduced the network of human relations in the Nazi camps to a false ‘friend-enemy’ dichotomy. The 1978 television soap opera Holocaust, starring Meryl Streep, further cheapened (and even glamorised) the enormity of Hitler’s genocide. Once that happens, Levi warned, the process of forgetting has already begun. In parenthesis: Levi disliked the term Holocaust, which, from the ancient Greek, means a sacrificial burnt offering to the gods: even by the standards of Antiquity, the Nazi genocide was not a ritual offering of victims. Levi studiously avoided use of the term.

Another film that exploited trite oppositions between good and evil was Roberto Benigni’s 1997 Nazi death-camp comedy Life is Beautiful. The film, which Levi fortunately did not live to see, was calculated to promote a roseate glow of hope in audiences when the reality is that the Nazi death camps did not allow for hope. Other Auschwitz-themed films likewise culpably divided the field between ‘us’ and ‘them’. Tim Blake Nelson’s 2001 The Grey Zone, about a Sonderkommando revolt which took place at Auschwitz in the autumn of 1944, starred Steve Buscemi and Harvey Keitel. Unfortunately, Hollywood celebrities jar in films that seek to answer the central question: how could the country that gave us Bach and Goethe commit the murder of millions of Jews?

Unsurprisingly, The Drowned and the Saved was seen by Italians on its publication 40 years ago as a determinedly grim and tenebrous work. Levi offered his readers few consolations. Ten years earlier, in his 1977 essay ‘Story of a Coin’, he explored the life of the Polish-Jewish industrialist Chaim Rumkowski, who, with Nazi connivance, set himself up as elder of Lodz ghetto in subjugated Poland and exploited fellow Jews for personal gain. The ‘alarming’ (as Levi called it) subject of wartime Jewish collaboration found its apotheosis in this morally ambiguous figure whose reign over the ghetto came to an end when he was himself deported to Auschwitz. Rumkowski was not quite a monster, in Levi’s view: he may even have saved Jewish lives. As a denizen of the grey zone, Rumkowski is left with an ambivalent legacy as both hero of, and traitor to, the Jewish people.

A totalitarian system such as National Socialism does not ‘sanctify’ its victims, said Levi; rather, it engulfs and converts them to its methods. In ‘The Grey Zone’ he quotes admiringly from Manzoni’s 1827 historical novel of injustice in 17th-century Lombardy, I promessi sposi (The Betrothed), a despairing moral treatise on the contagion and abuse of power: ‘Provocateurs, oppressors, all those who in some way injure others, are guilty, not only of the evil they commit, but also of the perversion into which they lead the spirit of the offended.’ Manzoni’s insight was consonant with Levi’s analysis of power relations within the grey zone. Levi told a journalist that if he had to rescue two Italian writers from a library fire, they would have to be ‘Manzoni and Dante’.

Levis’ essay is haunted by the guilt he said he sometimes felt as a survivor and the awful question: ‘perché io e l’altro no?’ (‘Why me and not others?’). As long ago as 1955, Levi confessed to his overwhelming ‘vergogna’, shame, at belonging to the same species that built Auschwitz. A part of him even believed he had colluded at Auschwitz through his work as a chemist. His guilt that others had died in his place, that he was alive thanks to a privilege he had not earned, was amplified and interrogated in The Drowned and the Saved. ‘I know my guilt is quite unjustified’, Levi told the Italian writer Gian Luigi Piccoli in 1980, ‘but I can’t clear it from my conscience.’

Some ex-deportees in Levi’s circle in northern Italy believed they had survived the Nazi camps not by cunning or collaboration, but by force of their virtue: ‘per belle virtù’. The survivors – the ‘saved’ – were the best. The Drowned and the Saved, however, appears to suggest that survival was not (or not necessarily) evidence of virtue and that the morally compromised were more likely to endure. Those who fathomed the depths of human degradation in the Nazi camps were the ones who died and did not come back to tell the tale. The weight of this distinction between the ‘drowned’ and the ‘saved’ – signalled by the book’s Dantesque title – is felt on almost every page. In Hans Memling’s massa damnationis with its devils and pitchforks Levi may even have seen the ghost of the sordid Rumkowskis of this world.

The subject matter of The Drowned and the Saved, a book that goes to the heart of recent moral history, left Levi feeling depleted and intellectually drained. He had lived with Auschwitz for over four decades. The writing of If This is a Man 40 years earlier had been regenerative for Levi – a journey from pain to consolation – but The Drowned and the Saved offered no such moral recovery. The world that Primo Levi once believed reformed after the war was built on very shaky ground. Nietzsche’s ‘festival of human cruelty’ was far from over: Auschwitz happened once, Auschwitz can happen again.