This collection features contributions by renowned scholars, each of whom focuses on a particular theory or tradition of international law, a region, an institutional regime or a particular subject-matter, and considers how that perspective impacts on our understanding of the role and status of non-State actors. The book takes a critical approach as it seeks to gauge the extent to which each conception and understanding of international law is instrumental in the perception of non-State actors. In doing so the volume provides a wide panorama of all the contemporary legal issues arising in connection with the growing role of non-state actors in international-law making and international law-enforcement processes.