This chapter focuses on Cornelius Castoriadis's critical and topical engagement with the crisis of the latter and stresses its relevance for contemporary critical theory. First, it examines Castoriadis's correlation of the crisis of modern societies with the concept of reification and the impact of class struggles. Crisis is discussed as being inherent to the contradictory and antagonistic constitution of the capitalist social relations and Castoriadis is situated in a critical dialog with Lukacs and Adorno. Second, the chapter critically explores Castoriadis's subsequent view of the crisis as a phenomenon ensuing from the conflict between the social imaginary significations of "autonomy" and the unlimited expansion of "rational mastery", which has led to the eclipse of the project of autonomy. Finally, it engages with Castoriadis's argument that modern societies are moving from a state of permanent crisis to a situation of decline and decomposition, manifested in the rising tide of insignificancy and new forms of barbarism.