Known as the ‘Angel of Death’, he consigned arrivals to the gas chambers and carried out appalling medical experiments on Jews, most of whom died in agony without anaesthetic.
He escaped to Brazil at the end of the war and began his memoir in May 1960, musing on eugenics, art, religion, women’s rights and predictions for the future of mankind.
Auctioneer Alexander Autographs of Connecticut refused to identify the seller who acquired the diary after Mengele died in 1979 but said the source was ‘close’ to the Mengele family, and still lives in Germany.
Auction house president Bill Panagopulos said: ‘Make no mistake about it – I have no sympathy for these monsters. My father’s home town was wiped out by the Nazis in a reprisal action.
‘But it is of vital importance that such documents remain available as tangible evidence of the evil deeds of the past, as well as to provide further pieces of history’s puzzle.’