European history of the past century is full of examples of philosophers, writers, and jurists who, whether they lived in democratic, communist, or fascist societies, supported and defended totalitarian principles and horrific regimes. But how can intellectuals, who should be alert to the evils of tyranny, betray the ideals of freedom and independent inquiry? How can they take positions that, implicitly or not, endorse oppression and human suffering on a vast scale? In profiles of Martin Heidegger, Carl Schmitt, Walter Benjamin, Alexandre Kojeve, Michel Foucault, and Jacques Derrida, Mark Lilla demonstrates how these thinkers were so deluded by the ideologies and convulsions of their times that they closed their eyes to authoritarianism, brutality, and state terror. He shows how intellectuals who fail to master their passions can be driven into a political sphere they scarcely understand, with momentous results for our intellectual and political lives.