The rules of treaty interpretation, codified in the Vienna Convention on the Law of Treaties, now govern the understanding of virtually all treaties, both in international law and within many national legal systems. As treaties increasingly influence a wide array of legal and policy areas, the ability to interpret them correctly has become essential for lawyers, diplomats, administrators, and other officials.This thoroughly updated third edition of Treaty Interpretation offers a clear and comprehensive guide to the modern rules of treaty interpretation and their practical application. It incorporates analysis of recent case law from international and national courts, developments in the work of the International Law Commission, and insights from the expanding academic literature on treaty interpretationThe book explains how the codified rules differ from domestic interpretive approaches and illustrates their use through real-world examples. With over four decades of jurisprudence now available, this edition draws on a rich body of case law to illuminate both the theory and practice of treaty interpretation.Whether dealing with international agreements or domestic legislation with international dimensions, legal professionals today are increasingly likely to encounter treaty provisions. This book equips them with the tools to interpret such provisions accurately and effectively.