This book aims at advancing our understanding of the influences international norms and international institutions have over the incentives of states to cooperate on issues such as environment and trade. Contributors adopt two different approaches in examining this question. One approach focuses on the constitutive elements of the international legal order, including customary international law, soft law and framework conventions, and on the types of incentives states have, such as domestic incentives and reputation. The other approach examines specific issues in the areas of international environment protection and international trade. The combined outcome of these two approaches is an understanding of the forces that pull states toward closer cooperation or prevent them from doing so, and the impact of different types of international norms and diverse institutions on the motivation of states. The insights gained suggest ways for enhancing states' incentives to cooperate through the design of norms and institutions.