The Evil That Two Men Did

Adolf Hitler and Joseph Stalin, the two most powerful personifications of evil in this century, are still impossible to explain fully. They shouldered their way into politics as resentful, hate-filled egoists, but so did thousands of their contemporaries. To anyone scrutinizing the young Hitler or Stalin, writes Alan Bullock, the Oxford University historian, "a suggestion that he would play a major role in twentieth-century history would have appeared incredible." At 30, Hitler was a street-corner speechmaker in Munich, and Stalin was in prison for plotting an oil workers' strike in Baku.

"They developed over time," says Lord Bullock -- he became...