At times, the two men seem to be conducting an academic discussion, searching for shards of historical truth in a scholarly, courteous exchange marked by occasional flashes of humor.

Then there are moments when they wield verbal stilettos, while maintaining an exterior show of politesse.

"Adolf Hitler never used derogatory terms like `the Chosen People.' "

"No, he called the Jews parasites and bacilli."

"Yes, yes, it's all fanciful on your part."

British historian David Irving, who has sought to absolve Hitler from responsibility for the Holocaust, stands in the witness box in Room 73 of the Royal Courts of Justice jousting with attorney Richard Rampton.

Irving is suing Penguin Books and professor Deborah Lipstadt of Emory University in Atlanta for libel because she has written that he is a Holocaust denier and a "Hitler partisan" who has distorted history to try to exonerate the German dictator.

In her book "Denying the Holocaust," Lipstadt cites the generally accepted view that the Nazis killed 6 million Jews, vast numbers of them in extermination camps built for that purpose in Poland. Most historians believe the decision to carry out a systematic slaughter of Jews was decided at a conference held in a villa beside the Wannsee, a Berlin lake, on Jan. 20, 1942. The conference was attended by leading Nazi officials, but Hitler was not present.

Irving, a gray-haired, broad-shouldered man of 62 who looks and sounds the part of a mildly querulous academic, has nothing to lose in this case except his bank balance.

His professional reputation already is in tatters, and he has been barred from Germany and other countries that he says are essential to his historical research. It is not the first time Irving has come to court because of his Holocaust views. At a meeting in Munich, Irving dismissed reports that the Nazis used gas chambers to kill millions as a "propaganda story."

Denying the Holocaust is a crime in Germany, and Irving was charged, found guilty in May 1992 and heavily fined.

But should he win this libel case, he could walk away with millions and claim a victory for himself and those who share his views about the Third Reich.

Even his critics acknowledge that Irving is the most scholarly of the Holocaust deniers, and few people have searched the wartime archives as thoroughly--and benefited as well from the recollections and diaries of old Nazis whom he befriended.

His memory is prodigious. Rampton produces relatively obscure archival documents, and Irving rattles on at length about minor Nazi bureaucrats mentioned in them, or says with great confidence this is a document he has never seen.

The trial, which began last week, is expected to continue for three months and soon will move, briefly, to the site of the Nazi extermination camp at Auschwitz. Irving has never been there, but he contends its gas chambers were built by the Poles after the war as a tourist attraction.

He does not deny the Nazis killed Jews and other civilians on a large scale. But he does deny it was official policy and contends Hitler knew nothing about it until October 1943.

"If the killing had been systematic, it would have been done with more efficient means," he told the court.

Rampton: "The Germans were acting in a random, haphazard way?"

Irving: "Yes . . . It was a totally ramshackle operation, a total lack of system."

While evidence of the systematic nature of the Holocaust is overwhelming, the basis of Irving's suit is that he has been falsely accused of denying the Holocaust, so he accepts the term freely in court.

"I'm not an expert on the Holocaust and don't intend to become one for the purposes of this trial," he says when Rampton asks what happened in one of the Nazi camps.

Rampton repeatedly reads documents referring to the deportation of thousands of Jews to the camps and asks Irving to accept that any reasonable person would conclude they were sent there for extermination.

Irving resolutely insists he will not draw inferences from documents that do not specifically support that conclusion.

Rampton asserts that Irving has no evidence to contradict the possibility that Treblinka, Sobibor and Belzec were built as extermination camps.

"That's a very fair statement," Irving replies.

Throughout, he denies Hitler ordered the Final Solution, and says that no document has surfaced directly tying Hitler to the extermination efforts. Nevertheless, reputable scholars have no doubt that he was informed and gave ultimate approval for the Holocaust.

Even in 1942, Irving says, Hitler was talking of shipping the Jews to Madagascar to begin new lives, but the operation could not be carried out because of the naval war.

In Hitler's "table talks" with his Nazi henchmen, Irving says, there was never any suggestion Jews should be systematically killed.

At one point Irving, referring to the lack of an extermination order from Hitler, tells Rampton: "I have to remind you of the basic principle of English law that a man is innocent until he is proved guilty. Am I right?"

During one break in the proceedings, a woman accosts him and says her parents were gassed at Auschwitz.

"You may be pleased to know that they almost certainly died of typhus, as did Anne Frank," Irving replies.

Rampton sometimes betrays a lack of familiarity with the historical record. The trial almost certainly will become more interesting when Irving, who is acting as his own attorney, cross-examines expert witnesses assembled by the defense.

The son of a British naval commander who served in both world wars, Irving has been a Germanophile since his teens. He dropped out of university and spent a year as a steelworker in the Ruhr while learning German.

He came to prominence with a book on the bombing of Dresden and biographies of Field Marshal Erwin Rommel and Hitler's deputy, Rudolf Hess.

His most controversial book, "Hitler's War," was published in 1977 and sought to absolve Hitler from responsibility for the mass murder of Jews. Irving offered a cash reward to anyone who could find a document directly linking Hitler to the Final Solution.

In the book he said a handwritten note by Heinrich Himmler, head of the SS, quoted a Hitler order of Nov. 30, 1941, that there was to be "no liquidation" of Jews. As late as October 1943, he said, Hitler was still forbidding liquidation of Jews but was disobeyed by the SS.

Irving contended that, despite his public image, Hitler was a weak political leader who lost control over those serving under him.

In 1979 Irving's German publisher apologized for printing in "Hitler's War" that Anne Frank's diary was a forgery and paid compensation to her family.