This book considers the exercise of sovereign powers by international organizations that include the United Nations, the World Trade Organization, and the European Union in order to answer fundamental questions about the relationship between an international organization and its Member States. In their membership of international organizations, States must confer some of their sovereign powers upon those organizations. In this book, Sarooshi develops a three-tiered typology of conferrals which ranges from agency relationships, to delegations of authority, to full transfers of power. The legal aspects of these conferrals are examined, and their implications for the growing importance of international organizations in international relations are assessed.