This book examines the cycle of struggles that has gone through current societies from the 1960s to the present. It presents an analytical description of the great lines of force that have defined the problems and objectives of the social, political and trade union movements during the last thirty years and of the restructuring that capitalist societies have experienced in response to the challenge posed by them. It concludes with a theoretical analysis of various aspects of the crisis of the Marxist paradigm (law of value / political representation) and of the possible ways to proceed with its creative synthesis.