This book compares the genocide perpetrated by both Nazism and Communism. Both political systems were evil yet, when compared, they lose some of their power to shock. The book considers: the different receptions given to Nazism and Communism; whether people can behave “rationally” in contexts of great wickedness; whether the Communist or Nazi worldview was more “rational” the relationship between post-war memories and history; and how atrocities are remembered by society and how intellectuals construct them. The editors argue that these twentieth-century evils invite comparison if only because of their traumatic effects and that we have an obligation to understand what happened and an obligation to understand how we have dealt with it.