Hitlers rise to power led to totalitarianism in Germany and ultimately into the cataclysms of the Holocaust and World War Two. It also spurred the exodus of a wave of intellectuals from Central Europe. In this seminar we examine major works by émigré intellectuals who combined sweeping historical perspective, theoretical ambition, and personal commitment as they strove to understand what had gone wrong. Moving chronologically, we start with theories of the character and origins of totalitarianism written between the rise of Hitler and the outbreak of world war, and then move on to works written during the war, and finally in its aftermath. In doing so we treat and compare émigrés located in diverse scholarly fields, who held widely differing political views, as contributors to a dramatic unfolding debate about the cataclysmic problem of totalitarianism.