Holocaust-denial is a body of work which attempts to prove that the Holocaust did not happen. However, this is not something that should just offend Jewish people, because by trying to disprove the Holocaust, revisionists also deny by extension the attempted genocide of the "others" (Poles, Gypsies, homosexuals, the disabled, etc.).
Drobnicki, John A., "The Holocaust Did Happen" (1993). CUNY Academic Works.