Bringing together the various heterodox traditions, groups and scholars that came under the heading of Open Marxism for the first time, this book assesses the evolution of Open Marxism from the initial usage of the term by Kostas Axelos in France in the 1950s and the journal, Arguments, principally the ‘anarchist Marx’ of Maximilien Rubel and the ‘Libertarian Marxism’ of Daniel Guérin, through Open Marxism as it was developed in Eastern Europe, especially in the scholarly work of Karel Kosik in Czechoslovakia, the work of the Polish Open Marxists and the Praxis group in Yugoslavia, to Johannes Agnoli’s work in post-1968 (West) Germany, and finally to the work developed by Bonefeld, Clarke, Gunn and Holloway within the framework of the Conference of Socialist Economists (CSE) in Britain since the 1980s. Its comprehensive study of the historical development of Open Marxism in all its various guises and forms reasserts the rich insights of its devastating critique of social democracy, Leninism-Stalinism and the Althusserian structuralist paradigm. It introduces a new readership to Open Marxism’s negative, fundamental, and destructive critique of capitalism and examines the practical relevance of its subversive thinking to the contemporary struggle for a free and open socialist society.