Cornelius Castoriadis was an influential Greek-French philosopher, economist, psychoanalyst and social critic. Director of Studies at the École des Hautes Études en Sciences Sociales in Paris for many years, his encyclopaedic intellectual range broke down disciplinary boundaries and gave his work a resonance that is still felt throughout the social sciences and humanities. After an early career characterized by involvement in Marxist circles and a period as an economist for the OECD, he later distanced himself from Marxism and developed a dynamic new perspective that centred upon his ideas of autonomy and the social imaginary. These radical conceptual innovations underpinned his vision of social and political change as a function of each society’s ability to creatively institute its own self-conception and create radical discontinuities with the past. His magnum opus The Imaginary Institution of Society: Creativity and Autonomy in the Social-Historical World is published by Polity.