 In 1988, the American historian Arno J. Mayer published a book entitled Why Did the Heavens Not Darken?, which did not explicitly deny the Holocaust, but lent support to Holocaust denial by stating that most people who died at Auschwitz were the victims of "natural causes" such as disease, not gassing. Mayer also cited the works of Holocaust deniers Arthur Butz and Paul Rassinier in his book's bibliography. Critics such as Lucy Dawidowicz criticized Mayer's citation of deniers, and argued that his statements about Auschwitz were factually incorrect. Holocaust expert Robert Jan van Pelt has noted that Mayer's book is as close as a mainstream historian has ever come to supporting Holocaust denial. Holocaust deniers such as David Irving have often cited Mayer ’ s book as one reason for embracing Holocaust denial. Though Mayer has been often condemned for his statement about the reasons for the Auschwitz death toll, his book does not deny the use of gas chambers at Auschwitz, as Holocaust deniers often claim.
