An introduction to the critical theory of the Frankfurt School, providing an assessment of thinkers such as Pollock, Marcuse, Horkheimer, Adorno, Neumann, Lowenthal, Fromm, Kirchheimer and Habermas, and the political and intellectual context in which they worked. The account considers the political context of the formative work of the School against the background of the Weimar Republic and of Nazi Germany. It contrasts this with the very different background of 1950s Germany in which Habermas embarked on his academic career, and goes on to discuss the enduring relevance of critical theory to the contemporary political agenda. In particular, Stirk illustrates the continuing validity of the Frankfurt School's criticism of positivist, metaphysical, and, more recently, postmodernist views, and its members' attempts to incorporate psychological perspectives into broader theories of social dynamics. He assesses the School's contribution to key areas of contemporary debate including morality, interest, individual and collective identity and the analysis of authoritarian and democratic states.