If the past century will be remembered for its tragic pairing of civilized achievement and organized destruction, at the heart of darkness may be found Hitler, Stalin, and the systems of domination they forged. Their lethal regimes murdered millions and fought a massive, deadly war. Yet their dictatorships took shape within formal constitutional structures and drew the support of the German and Russian people. In the first major historical work to analyze the two dictatorships together in depth, Richard Overy gives us an absorbing study of Hitler and Stalin, ranging from their private and public selves, their ascents to power and consolidation of absolute rule, to their waging of massive war and creation of far-flung empires of camps and prisons. The Nazi extermination camps and the vast Soviet Gulag represent the two dictatorships in their most inhuman form. Overy shows us the human and historical roots of these evils.