That Martin Heidegger supported National Socialism has long been common knowledge. Yet the relation between his philosophy and political commitments remains highly contentious and recently has erupted into a vociferous debate. Boldly refuting arguments that the philosopher"s political stance was accidental or adopted under coercion, Rockmore argues that Heidegger"s philosophical thought and his Nazism are inseparably intertwined, that he turned to National Socialism on the basis of his philosophy, and that his later evolution is largely determined by his continuing concern with Nazism. After developing a framework that clearly outlines the interrelation of Nazism and Heidegger"s philosophy, Rockmore analyzes the famous rectoral address the philosopher delivered in 1933 upon becoming rector of the University of Freiburg. In that speech Heidegger sought to ground politics in philosophy. Rockmore examines the inseparable relation of politics and philosophy in Heidegger"s Being and Time, the recently published Contributions to Philosophy (written from 1936 to 1938), and the interpretations of Hölderlin, Nietzsche, and technology. In his conclusion Rockmore considers the ongoing discussion of Heidegger"s thought and Nazism in France. Combining extensive documentation of the Heidegger controversy with philosophical and historical analysis, this book raises profound questions about the social and political responsibility of philosophy.