As international organizations become ever more prominent in global politics it is increasingly urgent to understand their power, their limits, and their effects. Now in its fourth edition, this leading textbook provides the definitive introduction to modern international organizations, from the legal charters of their beginnings, to the issues they engage with in the contemporary world. In his analysis of the United Nations, the World Trade Organization, the International Criminal Court and ten other prominent global institutions, Hurd combines legal, empirical, and theoretical approaches in an accessible and cohesive package. Fully revised and updated, this latest edition includes topical cases and controversies involving international organizations, such as Brexit, trade wars, environmentalism, forced migration and border disputes. It will be of interest to undergraduate and graduate students taking courses in international organizations, international institutions, global governance, and international law.