Responding to Alain Badiou's "communist hypothesis", the leading political philosophers of the Left convened in London in 2009 to take part in a landmark conference to discuss the perpetual, persistent notion that, in a truly emancipated society, all things should be owned in common. This volume brings together their discussions on the philosophical and political import of the communist idea, highlighting both its continuing significance and the need to reconfigure the concept within a world marked by havoc and crisis.