Lewy draws on a wealth of previously untapped sources, including letters and diaries of soldiers who served in Russia, the recollections of Jewish survivors, archival documents, and most importantly, the trial records of hundreds of Nazi functionaries. The result is a ghastly, extraordinarily detailed portrait of the Holocaust perpetrators, their mindset, and the motivations for their actions.

Combining a rigorous historical analysis with psychological insight, the book explores the dynamics of participation in large-scale atrocities, offering a thought-provoking and timely reflection on individual responsibility for collective crimes. Lewy concludes that the perpetrators acted out of a variety of motives--a sense of duty, obedience to authority, thirst for career, and a blind faith in anti-Semitic ideology, among others. A witness to the 1938 Kristallnacht himself and the son of a concentration camp survivor, Lewy has searched for the reasons of the Holocaust out of far more than theoretical interest: it is a passionate attempt to illuminate a dismal chapter of his life--and of human history--that cannot be forgotten.