From January to April 2000 historian David Irving brought a high-profile libel case against Penguin Books and Deborah Lipstadt in the British High Court, charging that Lipstadt’s book, Denying the Holocaust (1993), falsely labeled him a Holocaust denier. The question about the evidence for Auschwitz as a death camp played a central role in these proceedings. Irving had based his alleged denial of the Holocaust in part on a 1988 report by an American execution specialist, Fred Leuchter, which claimed that there was no evidence for homicidal gas chambers in Auschwitz. In connection with their defense, Penguin and Lipstadt engaged architectural historian Robert Jan van Pelt to present evidence for our knowledge that Auschwitz had been an extermination camp where up to one million Jews were killed, mainly in gas chambers. Employing painstaking historical scholarship, van Pelt prepared and submitted an exhaustive forensic report that he successfully defended in cross-examination in court.