In "Masses, Classes, Ideas", French philosopher Etienne Balibar explores the intrinsic relationship between abstract philosophy and concrete politics. He discusses the influence of political philosophy on collective movements, touching on issues of religious and class struggle, nationalism and racism, the Rights of Man and the Citizen, and property as a social relation. The text gathers together, in English, nine of Balibar's influential essays written over a decade. Together, they offer a provacative contribution to the project of renewing democratic theory.