Every day, Martin Zaidenstadt leaves his house in the Bavarian town of Dachau and makes a short bus journey to the former concentration camp. He walks across the vast camp grounds, crosses a small wooden bridge, and positions himself outside a brick building which houses the gas chamber and crematoria, "Europe's first comprehensive extermination facility".
There he tells anyone who will listen - and the Dachau memorial site is visited by nearly a million people a year - of the three and-a-half years he was imprisoned in the camp. And he tells them not to believe the sign explaining that the gas chamber was never used. The gas chamber was used, he insists: he remembers the screams.
An authentic survivor showing up a sanitised official history? Perhaps; but the problem that sent Timothy W. Ryback "in search of Martin Zaidenstadt" is that this old man is also prone to claiming that he has visited the camp "every day for 50 years", which he has not, or that Dr Joseph Mengele worked at Dachau, which he did not. No documentary evidence or survivor testimony exists to corroborate his account of his service in a Polish regiment, his capture by German forces (who seem never to have discovered that he was a Jew), and his eventual detention at Dachau.
The author's search for the truth about Zaidenstadt takes him to far-flung archives, to Zaidenstadt's home town, and into the recesses of the old man's addled memory. He manages to confirm that Zaidenstadt's account of his origins in north-eastern Poland, and of a particularly horrific pogrom there, is truthful. But this is as far as Ryback gets. Frustratingly, he makes no effort to illuminate his subject's life in the decades after the war, when Zaidenstadt, having given up on returning to a hostile Poland, lived quietly in Dachau, marrying a German woman and raising three children, running a small business from his home, attending the Catholic church and drinking with the locals - including former SS men. This Martin Zaidenstadt, and the Dachau he inhabited, remain unknown, perhaps unknowable.
In the face of the dizzying array of questions thrown up by this man, and this town - questions about place, memory, authenticity, perception, and the "genealogy of guilt" - Ryback displays an admirable modesty. He has no thesis to sell. But such modesty is something of a hindrance in this short book, because Ryback never manages to make his two stories - the story of Zaidenstadt's life and the story of post-war Dachau - converge. And while the shape of the book is defined by the "search" for Zaidenstadt, Ryback's exploration of the soul of the town of Dachau, a half century after the liberation of the camp, is, for this reader, far more compelling.
A New York Times reviewer, quoted on the jacket, said that "Ryback has staged a morality play about a town with enormous moral deficits". Ryback has done nothing of the sort. The Last Survivor is not a morality play - quite the contrary - and it is pure escapism to imagine that the "moral deficits" of Dachauers today are greater than those of the general run of humanity.
What Ryback's reportage suggests is that Dachauers have responded to the dark history of their town with a thoroughly human mixture of self-pity and self-flagellation, angry denial and impotent goodwill. One thing is certain: they can offer no adequate redress for what took place in Dachau between 1933 and 1945. The best they can do is what, in his own way, Martin Zaidenstadt has done: keep on living, alongside all the ghosts.
Brendan Barrington is an editor and critic