European history of the past century is full of examples of philosophers, writers, and scholars who supported or excused the worst tyrannies of the age. How was this possible? How could intellectuals whose work depends on freedom defend those who would deny it? In profiles of six leading twentieth-century thinkers—Martin Heidegger, Carl Schmitt, Walter Benjamin, Alexandre Kojève, Michel Foucault, and Jacques Derrida—Mark Lilla explores the psychology of political commitment. As continental Europe gave birth to two great ideological systems in the twentieth century, communism and fascism, it also gave birth to a new social type, the philotyrannical intellectual. Lilla shows how these thinkers were not only grappling with enduring philosophical questions, they were also writing out of their own experiences and passions. These profiles demonstrate how intellectuals can be driven into a political sphere they scarcely understand, with momentous results. In a new afterword, Lilla traces how the intellectual world has changed since the end of the cold war. The ideological passions of the past have been replaced in the West, he argues, by a dogma of individual autonomy and freedom that both obscures the historical forces at work in the present and sanctions ignorance about them, leaving us ill-equipped to understand those who are inflamed by the new global ideologies of our time.