This book addresses conflicts involving different normative orders: What happens when international law prohibits behavior, but the same behavior is nonetheless morally justified or warranted? Can the actor concerned ignore international law under appeal to morality? Can soldiers escape legal liability by pointing to honor? Can accountants do so under reference to professional standards? How, in other words, does law relate to other normative orders? The assumption behind this book is that law no longer automatically claims supremacy, but that actors can pick and choose which code to follow. The novelty resides not so much in identifying conflicts, but in exploring whether, when, and how different orders can be used intentionally. In doing so, the book covers conflicts between legal orders and conflicts involving law and honor, self-regulation, lex mercatoria, local social practices, bureaucracy, religion, professional standards, and morality. Jan Klabbers has taught international law at the University of Helsinki since 1996 and has held visiting professorships in New York, Geneva, and Paris. He was director of the Centre of Excellence in Global Governance Research from 2006 to 2011 and has won a number of awards for excellence in teaching. He received his doctorate from the University of Amsterdam (with distinction), and his main publications include The Concept of Treaty in International Law (1996), An Introduction to International Institutional Law (2nd ed. 2009), Treaty Conflict and the European Union (2008), and, as coauthor, The Constitutionalization of International Law (2009).