Part I Three perspectives - political science, policy studies, and international law: private in form, public in purpose - NGOs in international relations theory, Bob Reinalda international policy arrangements of state and non-state actors, Bas Arts non-state actors in international law, Math Noortman. Part II International relations theory, nation-states and non-state actors: the relevance of being important or the importance of being relevant? - state and non-state actors in international relations theory, Anton Weenink the de-territorialization of political authority by the European Union, Hans Vollaard defining national preferences - the influence of international non-state actors, Femke Van Esch non-state actors in foreign policy making - a policy subsystem approach, Bertjan Verbeek, Philip Quarles Van Ufford theorizing power relations between NGOs, intergovernmental organizations and states, Bob Reinalda, Bertjan Verbeek. Part III Non-state actors in international areans: the influence of trade unions on the social controversy in the International Labour Organization and its working party, Gerda Van Roozendaal co-operation and discord - NGOs and the NAFTA, Barbara Hogenboom the impact of environmental NGOs on international conventions, Bas Arts multinational enterprises and international climate policy, Ans Kolk. Part IV International civil society: Building transnational advocacy networks before 1965 - diffusion from the Indian Nationalist Movement to the AMerican Civil Rights Movement, Sean Cabot the impact of private aid agencies on civil society development, Kees Biekart early-warning by NGOs in conflict areas, Edwin Bakker the Russian mafiya - a private actor in international relations?, Anton Weenink. Part V Conclusion: The quest for unity in empirical and conceptual complexity, Math Noortman, Bas Arts, Bob Reinalda.