Was the extermination of the Jews part of the Nazi plan from the very start? Arno Mayer offers astartling and compelling answer to this question, which is much debated among historians today.In doing so, he provides one of the most thorough and convincing explanations of how the genocidecame about in Why Did the Heavens Not Darken?, which provoked widespread interest and controversywhen first published.

Mayer demonstrates that, while the Nazis' anti-Semitism was always virulent, it did not becomegenocidal until well into the Second World War, when the failure of their massive,...