Two tyrants. Each responsible for the death of millions. This compelling book on Hitler and Stalin - the culmination of thirty years' work - examines the two leaders during the Second World War, when Germany and the Soviet Union fought the biggest and bloodiest war in history.

Hitler's charismatic leadership may contrast with Stalin's regimented rule by fear; and his intransigence later in the war may contrast with Stalin's change in behaviour in response to events. But as bestselling historian Laurence Rees shows, at a macro level, both were prepared to create undreamt-of suffering - in Hitler's case, most infamously the Holocaust - in order to build the utopias they wanted. Using previously unpublished, startling eyewitness testimony from soldiers, civilians and those who knew both men personally, Laurence Rees - probably the only person alive who has met Germans who worked for Hitler and Russians who worked for Stalin - challenges long-held popular misconceptions about two of the most important figures in history.