This compelling book on Hitler and Stalin - the culmination of 30 years' work - examines the two tyrants during WWII, when Germany and the Soviet Union fought the biggest and bloodiest war in history. Yet despite the fact they were bitter opponents, Laurence Rees shows that Hitler and Stalin were, to a large extent, different sides of the same coin. 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 at a macro level, both were prepared to create undreamt-of suffering, destroy individual liberty and twist facts in order to build the utopias they wanted, and while Hitler's creation of the Holocaust remains a singular crime, Rees shows why we must not forget that Stalin committed a series of atrocities at the same time.