We consider the purpose and design of the World Trade Organization (WTO) and its predecessor, the General Agreement on Tariffs and Trade (GATT), and review recent developments in the relevant theoretical and empirical literature. We describe the GATT/WTO architecture and briefly trace its historical antecedents. We suggest that the existing literature provides a useful framework for understanding and interpreting central features of the design and practice of the GATT/WTO, and we identify key unresolved issues.WTO, GATT, trade agreements, terms-of-trade theory