Jean-Claude Pressac

Jean-Claude Pressac (3 March 1944 – 23 July 2003) was a French pharmacist by profession, who became a published authority on the Auschwitz concentration camp homicidal gas chambers deployed during the Holocaust in World War II. He was the author of the 1989 book Auschwitz: Technique and operation of the gas chambers among other publications on the subject, which demonstrated the technical possibility of mass killing by gas chambers during the Holocaust, thus debunking many falsehoods promoted by Holocaust deniers.

Pressac's path to this scholarship was singular. Initially drawn in the late 1970s to Holocaust denial through contact with Robert Faurisson, his archival research on site at Auschwitz ultimately convinced him of the reality of the mass killings. He severed ties with Faurisson in April 1981 and reoriented his work toward establishing the technical facts of the extermination. Drawing on blueprints from the Nazi construction office at Auschwitz-Birkenau that had gone unexamined for decades, and working under the auspices of the Klarsfeld Foundation, Pressac produced what became the first comprehensive technical study of the extermination machinery grounded exclusively in material and documentary evidence. His work received a divided reception: while widely praised by historians for its documentary rigour, its cold technical approach drew strong criticism for excluding survivor testimony entirely.