This book includes up-to-date studies of regional integration efforts in all major parts of the world, especially North America, South America and East Asia. In many cases these efforts are compared with the EU, where integration has progressed much further. Some important questions are asked: What explains the variation in achievements? What kind of agreements and institutions are needed to produce regional integration? Is 'pooling and delegation' of sovereignty necessary to overcome 'collective action problems'? How important is regional leadership? Various schools of thought are represented in the book, so different approaches are used and diverse conclusions arrived at. It appears that great power asymmetries in a region can make integration difficult if a dominant state is not willing to accept a relatively complete contract - as the United States was in the case of NAFTA - or accept supranational institutions. The acceptance of supranational institutions in Europe was facilitated by the relative symmetry among the core group of larger states, including France and Germany. In South America or East Asia, such symmetry did not exist and the dominant states - like Brazil in the case of MERCOSUR - were not willing to bind their hands through complete contracts or supranational institutions.This book is a major new contribution to the literature on regional integration. The book should appeal to theorists, policymakers, students and other readers concerned about world developments. It will also serve a place on courses covering international political economy, international relations and regional integration, at both undergraduate and graduate levels.