Many scholars of international relations in Asia regard bilateralism and multilateralism as alternative and mutually exclusive approaches to security co-operation in the region, arguing that eventually multilateral associations such as ASEAN will in time replace the system of bilateral alliances which were the predominant form of security co-operation in Cold War times and which continue as the primary means of the United States' engagement with the region, for example the US alliances with Japan and South Korea. This book contends, on the other hand, that bilateralism and multilateralism are not mutually exclusive, and that bilateralism is likely to continue strong even as multilateralism strengthens. This book explores a wide range of issues connected with this question. It discusses how US bilateral alliances have been reinvigorated in recent years, examines how bilateral and multilateral approaches to specific problems can work alongside each other, and concludes by considering how patterns of international security are likely to develop in the region in future.