The collective complaints procedure was created in 1995 as an optional quasi-jurisdictional monitoring mechanism specific for the protection of social rights, within the framework of the Council of Europe treaty system of the European Social Charter. In recent years, the importance and use of this procedure has increased considerably, in the context of a number of serious economic and social crises which are impacting negatively on the effective enjoyment of social rights in Europe. This short monograph explores and clarifies the specific features, the potential and limits of the collective complaints procedure, intended as a sui generis instrument for the protection of social rights, in the light of its evolutive application by the European Committee of Social Rights (the monitoring body of the European Social Charter) and its real impact on the state and conditions of social rights in the European countries concerned.