An account of the London trial of a libel suit filed against an American author, Deborah Lipstadt, by the British historian David Irving. She had called him "one of the most dangerous spokespersons for Holocaust denial" after he had argued that Hitler was not personally responsible for the genocide, and that nobody had been gassed at Auschwitz. Under British law, the burden of proof in libel cases lies with the defendant rather than the plaintiff. Hence Lipstadt was forced effectively to prove the "reality of the Holocaust." Here Guttenplan has done a lively job describing the arguments and the principal personalities involved in the case. It makes for fascinating reading -- and so does the judge's verdict in favor of Lipstadt, which was crushing for Irving. Guttenplan also asks questions about the knowledge of the past, the proper response to hate speech, the importance of the Holocaust for Jewish identity, and how history should be written. Unfortunately he is not very good at answering them, and his brief sketches of Holocaust literature are sometimes fuzzy and superficial. But he is still right in regretting the exclusion of witnesses' testimonies from the trial. Not only are documents too cold and gray, they are often as unreliable as the memories of perpetrators and victims.