The term ‘Frankfurt School’ is used widely, but sometimes loosely, to describe both a group of intellectuals and a specific social theory. Focusing on the formative and most radical years of the Frankfurt School, during the 1930s, this study concentrates on the Frankfurt School’s most original contributions made to the work on a ‘critical theory of society’ by the philosophers Max Horkheimer and Herbert Marcuse, the psychologist Erich Fromm, and the aesthetician Theodor W. Adorno. Phil Slater traces the extent, and ultimate limits, of the Frankfurt School’s professed relation to the Marxian critique of political economy. In considering the extent of the relation to revolutionary praxis, he discusses the socio-economic and political history of Weimar Germany in its descent into fascism, and considers the work of such people as Karl Korsch, Wilhelm Reich, Walter Benjamin and Bertolt Brecht, which directs a great deal of critical light on the Frankfurt School. While pinpointing the ultimate limitations of the Frankfurt School’s frame of reference, Phil Slater also looks at the role their work played (largely against their wishes) in the emergence of the student anti-authoritarian movement in the 1960s. He shows that, in particular, the analysis of psychic and cultural manipulation was central to the young rebels’ theoretical armour, but that even here, the lack of economic class analysis seriously restricts the critical edge of the Frankfurt School’s theory.