To raise the question of Heidegger and National Socialism, and to raise it precisely as a question rather than as an already foregone conclusion, is to enter into one of the darkest and most fiercely debated topics within Heidegger's thinking. Not only is this a question about philosophy and politics, of the Platonic guardian and his relation to the leadership of the polis; it is also – if not primarily – an ethical question about the support of one of Europe's greatest philosophers for perhaps the most terrible and violent regime in her history. There are so many dimensions to this question – of Heidegger's personal involvement as rector and academic leader (Führer) of Freiburg University from 1933 to 1934, of his fall from power and his claims of being persecuted in the Reich, of his post-war interrogation by the Freiburg University de-Nazification committee, of his public silence on the National Socialist years and the Holocaust, and his famous defence in the Spiegel interview of 1966. There is also the testimony of his contemporaries, including his students (Karl Löwith, Hermann Mörchen, Rainer Marten and Herbert Marcuse), his colleagues (Karl Jaspers), his friends/family (Elisabeth Blochmann, Elfride Heidegger, Heinrich Petzet) as well as the vast secondary literature that, after the publication of works by Victor Farias (1989), Hugo Ott (1993), Jacques Derrida (1989), and Philippe Lacoue-Labarthe (1990), spawned the notorious l'affaire Heidegger, whose echoes still resound in current discussions of the philosopher.