Ernest Mandel (1923–1995) was one of the best-known Marxist scholars active in the second half of the twentieth century. A leading member of the Fourth International, his books on capitalist economics, bureaucracies in the workers’ movement and on power and socialist strategy were translated into many languages. Democratic self-organisation of workers was a red thread that ran through all of his thinking. In Against Capitalism and Bureaucracy, Manuel Kellner presents the first and until now only comprehensive overview of Mandel’s theoretical and political contributions, arguing that his work remains important for the debates on a socialist alternative in the twenty-first century.