Half a century after their deaths, the dictatorships of Stalin and Hitler still cast a long and terrible shadow over the modern world. They were the most destructive and lethal regimes in history, murdering millions. They fought the largest and costliest war in all history. Yet millions of Germans and Russians enthusiastically supported them and the values they stood for. In this first major study of the two dictatorships side-by-side Richard Overy sets out to…