This volume features up-to-date studies of regional integration efforts in all major parts of the world, especially North America, South America, and East Asia. Comparisons are drawn between these efforts and those made in the EU, where integration has progressed much further. The book asks: 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? This work is a major new contribution to the literature on regional integration, and will appeal to theorists, policymakers, students and other readers concerned about world developments. It will also be of value to courses covering international political economy, international relations and regional integration, at both undergraduate and graduate level.