International organizations are increasingly important to global politics, law, and culture. Now in its fifth edition, this leading textbook provides the definitive introduction to modern international organizations by examining a dozen prominent global institutions. With a mix of legal, empirical, and theoretical approaches, the author examines timely cases where IOs are in the headlines today including on migration, Brexit, trade wars, and border disputes. This new edition is fully revised and updated, featuring new chapters on how global sports are organized by FIFA and the International Olympic Committee. The book explains the power and limits of international organizations by seeing how their legal authority interacts with politics in real-world controversies. It will be of interest to undergraduate and graduate students taking courses in international organizations, international institutions, global governance, and international law.