This is primarily a textbook for graduate and upper-level undergraduate students of law. However, practising lawyers and policy-makers who are looking for an introduction to WTO law will also find it invaluable. The book covers both the institutional and substantive law of the WTO. While the treatment of the law is often quite detailed, the main aim of this textbook is to make clear the basic principles and underlying logic of WTO law and the world trading system. Each section contains questions and assignments, to allow students to assess their understanding and develop useful practical skills. At the end of each chapter there is a helpful summary, as well as an exercise on specific, true-to-life international trade problems.