This new collection explores the origins and key issues of the Third Indochina War, which began in 1979. Drawing on unique documentation from all sides, leading contributors reinterpret and demystify the long-term and immediate causes of the Vietnamese-Cambodian and Sino-Vietnamese conflicts. They closely examine how both the links between policies and policy assumptions in the countries involved, and the dynamics – national, regional and international – drove them towards war. Rather than explaining the conflicts as determined by age-old resentments and suspicions or seeing war between the former allies as the necessary outcome of the conflicts of the 1970s, the contributors to this volume look at the concrete causes for the breakdown in cooperation and the road to war. This volume includes even-handed assessments of the roles of the major players, including a look at the beginnings of Thai-Chinese military cooperation in support of the Khmer Rouge. The subjects covered remain highly relevant to inter-state relations in South East Asia, where border issues are still a cause of tension. An updated chronology of events leading to the outbreak of hostilities is also included. This book will be of immense interest to all students of the Third Indochina War, Southeast Asian history and of international relations and war studies in general.