The third edition of this popular core textbook provides wide-ranging coverage of the structure, internal working, policies and performance of international organizations such as the UN, EU, IMF and World Bank. Such organizations have never been so important in addressing the challenges that face our increasingly globalised world. This book introduces students to theories with which to approach international organizations, their history, and their ability to respond to contemporary issues in world politics from nuclear disarmament, climate change and human rights protection, to trade, monetary and financial relations, and international development. Underpinning the text is the authors' unique model that views international organizations as actual organizations. Reacting to world events, political actors provide the 'inputs' which are converted by the political systems of these organizations (through various decision-making procedures) into 'outputs' that achieve varying levels of real-world impact and effectiveness. This is the perfect text for undergraduate and postgraduate students of Politics and International Relations taking courses on International Organization and Global Governance, as well as essential reading for those studying the UN, the EU and Globalization.