In his 1988 book "Why Did the Heavens Not Darken?", Mayer argues that Adolf Hitler ordered the Final Solution in December 1941 in response to the realisation that the Wehrmacht could not capture Moscow, hence ensuring Nazi Germany's defeat by the Soviet Union. In Mayer's opinion, the Judeocide (Mayer's preferred term for the Holocaust) was the horrific climax of the "Thirty Years' Crisis" that had been raging in Europe since 1914. The book considers the Holocaust as primarily an expression of anti-communism: