In a country waking up to a new future, these men have become potent symbols of Germany's nightmare past

This man's account of his childhood in Auschwitz has earned him the respect of Jews, the attention of Steven Spielberg and a place alongside Primo Levi in holocaust literature. He has been accused of writing a piece of fiction; This man has retired from an academic career founded upon his impeccable liberal credentials. He is a former SS officer and Himmler henchman who came back from the dead and remarried his own widow

Binjamin Wilkomirski's book of childhood memories, Fragments, makes harrowing reading. It details how during his boyhood his "playgrounds" were the concentration camps of Majdanek and Auschwitz, where he saw his friends being killed by sadistic guards. It is a story told in nightmarish, fragmented detail, with scenes too terrible to be remembered as anything but flashing images and threatening shadows.

In the book, people are glimpsed only as visual imprints - a boot, an arm, a uniform; scenes the boy witnessed are recalled in hallucinatory detail. A man smiles at the child: "suddenly his face is contorted, he turns away, lifts up his head, opens his mouth as if to let out a mighty cry. From underneath, against the light sky, I see the contours of his jaw and the hat which is sliding backwards. No cry comes out of his throat but a mighty, black geyser gushes forth from his neck as a vehicle crushes him against the wall of the house, and his bones are snapping." The reader is confronted with the death of Binjamin's father at the hands of Latvian militiamen, and that of this mother in the camp.

Since its appearance in 1995, the book has quickly established itself among the classics of Holocaust literature alongside the works of Primo Levi and Elie Wiesel, has been translated into 12 languages, put on the reading lists of schools and universities, and been awarded the National Jewish Book Award, the Jewish Quarterly Literary Prize and the Prix de la Memoire de la Shoah. Reviews the world over have reinforced its position as a monument to individual suffering, "dark, Proustian memories" and "poetic visions" (New York Times), carrying "the weight of an entire century" (Neue Zuricher Zeitung), and bearing out the tortuous way of bringing back what had long been repressed. The critic of the American publication The Nation even declared the book to be: "so moving, of such moral importance and so free of literary artifice that I ask myself whether I have any right to praise it... This man has survived - we don't know how, his sanity seems a miracle - and he gives this present of an almost perfect pain to a world that is still ready to destroy the innocent."

In an epilogue, the author tells that the authorities in Switzerland, where he grew up after the war, deprived him of his Jewish identity. He was called Bruno Doessekker, provided with a false birth certificate and adopted by a Swiss family, all in an effort to erase his early ordeal from his memory and from the world. Later, the publisher supplied more information about the genesis of these traumatic recollections. Only psychotherapy had been able to unlock his memories of life in the land of the dead.

Wilkomirski has since appeared at conventions and conferences, talking about this process, and has given readings and spoken in schools. He has been the guest of the Holocaust Museum in Washington DC and of several universities. He has also contributed to Steven Spielberg's epic oral history programme of interviews with survivors of the Holocaust.

The double existence as the Swiss Bruno Doessekker and as Binjamin Wilkomirski, the former Riga Jew, an earlier self which he has been able to rediscover only as a mature man, has now been called into question by a Swiss journalist, Daniel Ganzfried, who claims that his research into the author's background suggests that Wilkomirski spent his entire childhood in the Swiss cities of Biel and Zurich; that he was the illegitimate son of one Yvonne Grosjean, and was later adopted by the Doessekker family.

Ganzfried claims that Bruno Doessekker did not spend his early years in Eastern Europe, and says he has evidence that the boy spoke perfect Zurich dialect when he went to school at the age of seven in 1947, despite the fact that, according to his story, he would have only just arrived in Switzerland. Binjamin Wilkomirski, so Ganzfried claimed, had not preceded Bruno Doessekker, but it had been the other way round, a Swiss man imagining a previous existence as a Riga Jew that never happened.

Though the book has already gained the acclaim of historians and reviewers alike, details of the text are now beginning to be questioned by some historians, who believe that some episodes are historically impossible and others are extremely unlikely.

Faced with these accusations, Wilkomirski defended himself by claiming that all these questions had already been answered in the epilogue to his book, where he had made it clear that his "official" life had been exclusively Swiss, but claimed that that did not affect the authenticity of his memories, as it had been the policy of the Swiss government to provide new identities for surviving children in its care.

Wilkomirski said that "it has always been possible for my readers to read my book as literature". Whether the work is fact or fiction is a question that remains open to interpretation. The publishers are standing by the book as fact, and the author continues to appear on historical congresses and has even identified the house in Riga in which he spent his early childhood.

Such an aestheticisation of history may appeal to post-modernists, to whom the author Wilkomirski may become a hero and emblem of the indefinite play of signifiers, a dance of fact and fiction placing truth in the eye of the beholder. As a book tied to a definite historical events, however, and to questions of individual and collective guilt and responsibility, these delicate issues of truth and fiction erodes the very ground on which remembrance can be built, especially in Germany, a country that is still profoundly ill at ease both with its recent history and with the ways in which it can be remembered, and is dogged by a small but vocal group persistently doubting the veracity of the genocide of the Jews.

While there are genuine concerns that questioning the book may play into the hands of those who deny the Holocaust, it has also been pointed out that it would be far more damaging to leave it up to readers to determine whether this text should be treated as a document or as a work of fiction, the very ambiguity on which such a denial of genocide thrives.

Whatever the outcome, the affair is deeply embarrassing for all concerned, for Suhrkamp, Germany's most prestigious "intellectual" publishing house who accepted it (it did seek expert advice, and was encouraged to do so), and for those who sang its praises without questioning any possible inconsistencies. It also could be another blow for the already widely discredited therapeutic method of "retrieved memory", which has led to countless allegations of childhood sexual abuse, many of which have later been demonstrated to have no basis in fact.

The split identity of a supposed victim of the Holocaust is echoed by a second affair to occupy the German media: the case of Hans Schwerte, the former rector of Aachen University, a left-leaning liberal who gained his reputation by conciliating between the radical students and the conservative academic establishment during the Sixties. He was a leading literary scholar and adviser in educational questions to the German government, and a participant at the "Nuremberg talks", a forum of academics that set out to draft the "presentation and popularisation of left-wing liberalism". He is now living in a retirement home near Munich.

Schwerte was an expert on Goethe's scholar-hero Faust, who famously exclaimed "two souls live, woe is me, in this one chest". This turned out to be something of a literary and biographical irony when, in 1995, Schwerte was proved to be identical with one Hauptsturmfuhrer Ernst-Hans Schneider, a high-ranking SS officer and ideologue, who had supposedly been killed during the last days of the war.

With exemplary precision, Schwerte had relived the life of his earlier self. After conveniently "killing off" the Nazi Schneider, he had married Schneider's "widow", thus staying married to the same woman; had written a second doctoral dissertation; and was rewarded for his service to the education system with the merit cross of the German Federal Republic and several other medals, just as Schneider had been awarded the Iron Cross.

Schwerte enjoyed a successful and fruitful career as a literary scholar and university teacher before it was exposed that he had been, as Schneider, a prominent member of Heinrich Himmler's "Ahnenerbe" office, responsible not only for helping to formulate a National-Socialist vision of the German past and of "Germanic science", but also for requisitioning medical equipment for human experiments in the Dachau concentration camp. He had also called, at the end of the war, for a "total war of German science". After his exposure he was stripped of his honours. A Fascist wolf in liberal sheepskin, the ultimate opportunist, or, as he himself prefers, a man who lacked courage but who did atone through his later actions, Schneider/ Schwerte is emblematic for the culture of bureaucratic killers who changed their tune after the collapse of the vision of Germanic world domination that they had once believed in, and had helped to create.

In a final twist to his tale, the former professor who claimed for himself a second chance without personal accountability was forced to live by the name under which he had allegedly been accessory to murder, though criminal proceedings against him collapsed. Now, after the publication of two competing biographies, the discussions about his case have flared up again, discussions that deal not only with a single SS officer turned liberal academic, but with the entire phenomenon of former Nazis gaining important positions in post-war intellectual life.

The academic establishment that allowed Schwerte to rise to prominence, the Technical University of Aachen, is not keen to have its workings investigated too closely. The author of one of the biographies was threatened with legal proceedings should he claim any complicity with, and knowledge of, Schwerte's dual identity among university colleagues.

The celebrated and admired east-European Jewish victim who may just be gentile and Swiss (and confused), and the left-wing academic who has been a Nazi ideologue: these two so very different figures have, strangely, much in common. Both stories are symptoms of a nation's struggle to deal with its past, which on the one hand makes a fetish of victims, while on the other prefers the perpetrators to be dead, not part of their present and enmeshed in other people's lives. At the same time, it is no accident that these discussions did not take place earlier.

It took a new generation of historians and journalists without personal memories of this time to ask these questions, a generation that asks more directly and is less afraid to expose old taboos. This, of course, is also part of the current political problems Germany is experiencing. Along with less sentimentality comes, all too often, less sensitivity and less knowledge.

Whether Binjamin Wilkomirski or Bruno Doessekker, Hans Schwerte or Ernst- Hans Schneider, the shadow of the Third Reich is still looming over Germany and over a new crop of commentators struggling to make sense of it all in the language not coloured by personal involvement. Many aspects of Germany's official culture of remembrance have long been due for an overhaul: annual and ritualised chest-beating on selected dates has given rise to the temptation to dismiss the historical terror together with the modern manifestations of its continuing presence. Guilt that is learnt by rote can also lead to hatred.

The last 50 years of German history have been marked by attempts to reinvent the nation without allowing it to escape from its own shadow. As this task is taken over by a new generation, the two unconnected and bizarre episodes of Binjamin Wilkomirski and Hans Schwerte serve as a timely reminder of the nature of this task: to live with a past consisting of fragments that are neither imagined nor embellished, nor edited according to suitability - but confronted and, if possible, understood. That is challenge enough to a generation with no first-hand knowledge of the period, or indeed to any generation.