Was Hitler A Riddle? is the first comparative study of how British, French, and American diplomats serving in Germany assessed Hitler and the Nazi movement. These assessments provided the governments in London, Paris, and Washington with ample information about the ruthlessness of the authorities in Germany and of their determination to conquer vast stretches of Europe. Had the British, French, and American leaders acted on this information and taken measures to rein in Hitler, the history of the twentieth century would have been far less bloody: the second world war might well have been avoided, the Soviet Union would not have expanded into central and eastern Europe, and the world would have been spared the Cold War.