By that Levi meant it was a journey into a place only those who were inmates of what has been called "a man-made inferno" could begin to comprehend. With his background as a chemist, he studied his fellow Jews and his German tormentors with as cold an eye as it was possible to bring to the horrors he witnessed. Auschwitz, he insisted, where the average life expectancy was three months, "had nothing to do with the war". What it had to do with, however, eludes us still. It is not enough to explain away the industrial execution of hundreds of thousands of people by labelling its motivation "anti-semitic".
In his book, If This Is A Man, Levi referred to the men who persecuted him and slaughtered so many others as "evil and insane". Reason, however, prevented him from indulging in hatred. He preferred to write about what happened in Auschwitz as clinically as he was able. Language, he realised, was one of the tools used by the Nazis to keep secret what they were doing. Instead of writing "extermination" they wrote "final solution", not "killing by gas" but "special treatment".
To them, euphemism was like a dialect or a code or a form of shorthand. It allowed the population at large the opportunity to protest that they did not know what was being done in Hitler's name when, in fact, they knew only too well.
Martin Amis cites Levi as one of his many sources in The Zone Of Interest. Not the least of his indebtedness is obvious in his use of language. Here is a man, for example, such as Paul Doll, the commander of a camp that is obviously modelled on Auschwitz, who, even when he is talking to himself, avoids using words which, if overheard, would be difficult to misinterpret. Those spared annihilation are deemed "war essential", extermination is "by employment of the apt procedure", there is a department of "Race and Settlement" with a "Racial Researcher". Drunk and constantly popping pills, Doll welcomes new inmates as if they were guests at a holiday camp, promising them something good to eat and a hot shower. This is what he calls the "element of surprise". But the fact no one ever returns home belies the absurd notion these "settlers" are there voluntarily or for their own good.
This is hardly virgin soil for Amis. In Time's Arrow, published in 1991, he told the story of a Holocaust doctor who assists his superior, whom he modelled on Joseph Mengele, in his murderous experiments on Jews. In this new and breathtakingly brilliant novel, his approach is three-pronged. There is Doll, who is mentally sick and married to Hannah, who flaunts herself before him but will not allow him to touch her. Like those Nazis who testified at Nuremberg and elsewhere, Doll has rationalised to himself behaviour that defies rationalisation. Were he not engaged in such barbarism, he would be comical. As it is, he is one monster among many unleashed on his hapless victims by a regime that grows more brutal even as its doom becomes more apparent. In the name of National Socialism, Doll tells himself, "somebody's got to do it - the Jews'd give us the same treatment if they had 1/2 a chance, as everybody knows."
Forced to help Doll carry out his mission is Szmul, a young Jewish man. He is in charge of the camp's Sonderkommando, a so-called "special unit" whose task is to dispose of those killed in the gas chambers. It is a position that carries some privileges, such as a better diet and living conditions. But it is also one that has a limited term of office. Privy as they are to information the killers do not want broadcast, Sonderkommandos are destined soon to die too. They only have a few months' grace. Doll makes no attempt to hide this from Szmul, who must strive to make himself indispensable to a madman.
The only way Szmul can survive is by killing the Kommandant, who repeatedly torments him by reminding him of the date of his doom. "The urge to kill is like the bore of a river," Szmul writes, "a steepsided wave coming up against the flow. Against the flow of what I am or what I was. Part of me hopes the urge is there at the end."
But in this "psychotic" atmosphere, no one is safe. There is always someone watching and plotting. It also replete with irony and absurdity. It is not enough that human beings are being killed in numbers that are difficult to compute but animals are slaughtered too. When not killing Jews or "degenerates" or the old or the physically disabled or the mentally ill, Doll enjoys hunting deer. This is what stands for normality. In the environs of the camp, there are concerts and thes dansants and parties but there is no masking the stench of death, no obliterating the smell of burning corpses that spreads far and wide.
Amis's third narrator is Golo Thomsen, a German officer. More importantly, he is the nephew of Martin Bormann, Hitler's Private Secretary, which affords him some measure of protection. Good looking and sophisticated, he is the antithesis of Doll, his boorish superior.
When Thomsen and Hannah meet, the attraction is instant and potentially fatal. As the days pass and the war begins to go badly for the Germans, the imperative is to find a way out. It is clear that Hitler, whom Amis never names, not only wants to wipe out Jews but is also intent on destroying Germany. He has a final solution for everyone, all of whom must look in a mirror and see their souls. From this there is no escape. As Hannah realises towards the novel's end, "Under National Socialism ... We all discovered, or helplessly revealed, who we were. Who somebody really was. That was the zone of interest."
What Amis has achieved through fiction is to illuminate that which history can only hint at. By and large, we do not know what those who prosecuted the genocide in the first half of the 1940s thought or felt. Their testimonies were compromised, their accounts self-serving, designed to save their skins or excuse the inexcusable. Like Doll, Rudolph Hoss, who was in command of Auschwitz for three years and who presided over the extermination of a quarter of a million people, was insensitive, apathetic and obsessed with notions duty and efficiency. Killing had no effect on him. Everything could be explained by quoting numbers. Amis puts us where we would rather not go, into the head of someone like him, someone emotionally dead, to whom life is actually meaningless.
The Zone Of Interest may be his greatest book; it is that good. You want to put it down but you know you can't and you know that you shouldn't. It is inventive, awful, testing and, like Picasso's Guernica, incongruously beautiful. Would that Primo Levi were around to read it.
Martin Amis is at the Edinburgh International Book Festival tomorrow at 8pm