Philosophical speculation seldom attracts banner headlines, let alone threats of death. Yet such was the fate that overtook Herbert Marcuse in the late 1960s, when he was catapulted into international controversy as a prophet of the revolutionary student movement. Barry Katz shows that this startling change of fortune was consistent with the whole pattern of the philosopher's life and work. Katz follows Marcuse from his comfortable childhood in Berlin's Jewish bourgeoisie, through war, revolution, depression and Nazism, to the USA. He describes the young soldier's role in the German revolution; documents the exiled scholar's wartime activities in US intelligence; and evokes the very different political struggles that preoccupied the philosopher in the 1960s. Simultaneously, Katz gives a compelling interpretation of Marcuse's intellectual development, including his relationships with Benjamin and Lukács, Husserl and Heidegger, and the Frankfurt School. Marcuse's writings are carefully analysed - not only the famous works such as Eros and Civilisation and One-Dimensional Man, but also the early studies of the 'artist-novel' and of Hegel, and a crucial, unpublished essay on the poetry of the French Resistance.