Auschwitz, contrary to popular belief, was not a single camp; 39 satellite camps formed a malignant universe. Among the German companies who exploited Jewish slave labour in the camps were Bayer, Siemens, Agfa, BASF and Pelikan ink (used to tattoo prisoners).

As a boy, Czech-born historian Otto Dov Kulka was sent from Terezín ghetto to the Familienlager (family camp) of Auschwitz-Birkenau. A semblance of "normality" was allowed to continue in the camp: plays and concerts put on by the children and their parents were attended by high-ranking SS (among them Dr Josef Mengele). In time, however, most of the inmates were annihilated. Kulka survived by a fluke: he was in the infirmary at the time of the selections.

His experience of Auschwitz-Birkenau is the subject of this extraordinary book. Through testimony, photographs, dream journals and diary entries, Kulka interrogates his memories of one of the vilest places on Earth; the result is a sustained elegy for a lost childhood and a lost Jewish culture.

Memories that have haunted Kulka for more than 60 years  dead bodies in the snow, a summer's bright blue day  are interrogated in a series of profoundly moving, WG Sebald-like essays. The writing, at times dreamlike, creates an extraordinary sense of communion and intimacy with the reader. Of all the accounts of survival in the Nazi camps, few approach Kulka's for its civilised mission to bear witness. Landscapes of the Metropolis of Death, written in a documentarist's spare prose, is one of the essential books to emerge in recent years. If the Nazi crime cannot be reversed by the writer's pen, at least it can be chronicled and remembered. Kulka has done that and very much more.

It is probably a bad habit to read the end of a book first, but in this case it is irresistible. In the opening two paragraphs of Landscapes of the Metropolis of Death Otto Dov Kulka, an 80-year-old survivor of Auschwitz-Birkenau and emeritus professor of history at the Hebrew University in Jerusalem, explains that he has lived a split life. In his day job he was engaged in "strict and impersonally remote research" on the Holocaust; then, in his 60s, he began recording fragments of what he calls his "private mythology  of the Metropolis of Death. This book is an effort to bridge these two modes of knowing  historical scholarship and analysis on one side, reflective memory and the work of the imagination on the other.

The third paragraph sets the historical scene: the "family camp" (Familienlager) at Auschwitz-Birkenau for Jews from Theresienstadt, and especially the "children's block" that existed from the autumn of 1943 to its final liquidation in the summer of 1944. It ends with a footnote that refers readers to an appendix where they will find, reprinted, a learned article by the same Professor Kulka on this subject. It fills in the history we need to know and offers an example of the humanistic moral anthropology that informs the whole book. Begin at the end.

Why, Kulka asks, did the Germans transport several groups of Jews (5,000 at a time) from Theresienstadt  a relatively benign holding camp near Prague  to Auschwitz and allow them to live in family units, their heads unshaved and their own clothes on their backs? And why, after six months, did they then murder all of the first group, without a selection, on 7 March 1944 and then, in July 1944, almost all of the second group, excluding a few of those fit for labour? German archives provide the answer. In early 1944 questions about what was happening in the camps to which Europe's Jews were being shipped began to irritate the Nazi leadership. It negotiated with the International Red Cross to allow inspections of one camp. Theresienstadt was tarted-up for this purpose.

With the possibility that the IRC might want to confirm that other camps, specifically those in Poland, were equally salubrious, a shipment of Theresianstadt Jews were sent to Auschwitz-Birkenau and kept in a model family camp. When negotiations between the IRC and the Nazis stalled, these first 5,000 were murdered  after being forced to send back post-dated cards reporting that all was well. In May 1944 Himmler agreed to allow the IRC to inspect one Jewish labour camp in addition to Theresianstadt  Birkenau. A second transport had been kept alive there for such an eventuality. Then, on 23 June, Himmler was told that the Red Cross was satisfied with the conditions at Theresianstadt and also satisfied that it was a final destination and not a way station to some place worse. There was therefore no need for further inspections, the IRC said. And so, the family camp in Auschwitz-Birkenau was liquidated.

Kulka's appended article raises a second central question: why, after the first transport was liquidated and any illusion of escaping death had gone, did Jewish communal life, and indeed cultural life more generally, persist? There were efforts to save the sick; there were concerts, theatrical performances and schools. In a world in which death was a certainty, people acted as if there was a future. Men thought about going to their deaths bravely, as if it mattered to posterity, as if there would be a posterity. From the depths of the gas chambers they sang the confessions of "three secular movements of political messianism"  the Czech national anthem, the Zionist anthem, Hatikvah, and the International. A 20-year-old girl wrote poetry in the shadow of the crematoria that demonstrated her "abiding commitment to humanism" and to a moral ideal that rejected all violence and bloodshed. It survived; she was gassed and burned to cinders. We do not know her name.

Purposeful existence was sustained when it had lost all purpose. Kulka the scholar speculates that in the shadow of death, "historical, functional and normative values and patterns life were transformed into something in the order of absolute values". Thus from his "impersonally remote research", there emerges the profound vision of a moral philosopher. Perhaps the gap with which the book began is not so huge.

To return to the beginning. The author, as a middle-aged professor, attends a conference in Poland and takes a taxi to Auschwitz-Birkenau. He discovers that "it had been buried" and become "a vast grave from horizon to horizon", a melancholy landscape. This pastness of the past is the dominant trope of the book. Auschwitz-Birkenau is dead. Kulka descends as far as he can into a ruined crematorium; the names and images of those he remembers come to him. He picks up a brick and keeps it. It is 1978; he had been spared. The episode is illustrated by a small faded black and white photograph of him, strangely split down the middle because his taxi driver cannot handle a Leica. There are almost 50 old photographs and drawings dispersed throughout the book; it looks like WG Sebald's Austerlitz, and in some small sections drifts off into the memorial haze that many people appreciate in Sebald's last novel. Kulka's memoir  though he would deny the label  is both more haunting and more knowing.

He speaks for three selves: the boy who lived for more than a year within a couple of hundred metres of the gas chambers and the flaming, smoke-spewing crematorium chimney; the historian who reflects on the boy, discovers the fate of his mother and offers the testimony that has come into his hands of others living and dead; and the man  "the big boy", ie the narrator  standing before Kafka's gate "Before the Law", a gate that is about to close and that only he can enter. He is trying to preserve childhood landscapes in order to disclose their central message. That is: "the world, with the Metropolis and the immutable law of the great death having been, can no longer and will never again be able to free itself of their being part of its existence." As with the cosmos, so with the man.

Kulka and his parents came to Auschwitz-Birkenau from Theresienstadt in September 1943, and he left the camp, by then a strange ghost town, in the infamous death march of 18 January 1945. He and his mother were spared the wholesale annihilation of the first 5,000 in March 1944 because he was in the Birkenau hospital recovering from diphtheria and she was nursing him. A hospital was only metres from where thousands were murdered every day; surreal. He was sure that he would die that June when he was stopped at the gate by an SS guard  "Bulldog" (we see his picture)  and prevented from joining a group of men who had been selected for labour. But as his group of boys was marched back they were not directed toward the gas chamber but to another part of the camp to pull carts. Boys were cheaper than donkeys. Again, he survived. The child was spared the depths of torment felt by adults in the murderous Auschwitz universe because, the historian tells us, there was less dignity and autonomy to strip away. The flames of the ovens rose several meters high above the chimneys, but he lived a life in which the world of European high culture still mattered. An older boy, with whom he shared a hospital bunk, gave him a secreted copy of Crime and Punishment; a conductor organised a children's choir that sang Beethoven/Schiller's "Ode to Joy" in a lavatory barrack where the acoustics were good. Did he choose this music as an absurd, purposeless protest, meant to hold on to values that Auschwitz radically denied, or was it an act of sarcasm, "the outermost limit of self-amusement," Kulka asks. As a boy he did not know; he sang. And as a man he says that he has lived by the first explanation, an illusion perhaps "greater than the fierceness of sarcasm". Having sung Beethoven opposite the Auschwitz crematorium is, perhaps, part of Kulka's "private mythology", but is also, as readers know from the ending, evidence of the continuity of culture in hopeless circumstances.

Of course, as Primo Levi wrote, those who bear witness to the camps did not experience their worst. There are no witnesses from the grave, but there is speech from its brink. Among the most stunning pages of this book are the three poems in Czech written by the 20-year-old girl on slivers of paper, somehow saved by Kulka's father. Celan could not have know them when he wrote in his "Todesfuge" about graves in the air, but he might have:

Bleached skulls of hopelessness
Quiver on the barbed wire
And our ashes go to the four winds
Scattered in thousands of urns

We make a chain around the earth.

The boy grows up and becomes a historian. As an adult, he and his father visit the site of the Stutthof concentration camp, now a featureless field at the estuary of the Vistula. He includes a picture of them in front of a map of the camp that attempts to evoke what had once stood on these empty fields. What now remains is only meaningless landscape. The author's mother had arrived there in September 1944 after a deadly march from Auschwitz; she worked at searching shoes, sent there from other camps, for valuables and then repairing them before they were forwarded to Germany. The men  father and son  had learned from a survivor the circumstances under which their wife and mother had died. Arriving pregnant with a child conceived in Auschwitz, she gave birth to a healthy baby that her attendant women then strangled to avoid detection; she used a hidden diamond that her husband had given her to buy food for a critically sick comrade; the comrade lived; she then became ill; she did not live. Kulka says Kadish near where she was buried. He had seen his mother last when she marched out of the Auschwitz-Birkenau gate and, unlike Orpheus, she did not look back at him.

The historian Kulka contemplates the great tension in all Holocaust scholarship, that between treating it as ordinary history that can be known through ordinary means  the study of ideology, political dynamics, imperial and economic strategies  and treating it as an event of sublime horror that can only be grasped, if at all, through the collection of testimony and with resort to claims of "unrepresentability". Has he avoided writing this book all his life, he asks, just as he had side-stepped, as a boy, the mountains of skeletal corpses that had not yet been burned?

Perhaps. Kulka reports and reflects on his dreams and their sources. Kafka figures often; so does William Blake. Dreams of Doctor Mengele, not resembling the person he knew, but Mengele nevertheless, guiding Israeli visitors through the now buried Auschwitz; dreams of being lost in Prague and not being able to report to city hall; dreams that seem to track his father's research into the lives of survivors. Many are left uninterpreted. He seems to have recorded them here because by no longer sequestering them in the subconscious he can break the firewall between his professional and his inner life. Kulka has survived, he tells us, by keeping professional history on one side (relegated here to the appendix) and privately guarded memory and experience on the other (now here exposed to the full light of day). But he need not be so anxious about his professional probity. Primo Levi's testimony, it is often said, is that of a chemist: clear, cool, precise, distant. So with Kulka's work: this is the product of a master historian  ironic, probing, present in the past, able to connect the particular with the cosmic. His memory is in the service of deep historical understanding, rendered in evocative prose that is here eloquently translated from Hebrew.

A last dream: "God's grieving", illustrated with a picture from Blake's Illustrations of the Book of Job. It is interpolated with a report by his father of a visit to an aged rabbi who had served as a kapo in Auschwitz. "Where was God?" Kulka the elder asks. And the rabbi responds as he had in the "Metropolis of Death". "It is forbidden to ask that question, those questions, there and into eternity."

 Thomas Laqueur is finishing a book to be called The Work of the Dead.