This is a ground-breaking study of the diplomatic efforts in the aftermath of Vietnam’s 1978 invasion of Cambodia. In retrospect, the resolution of the Cambodian conflict marked an important shift in the international relations landscape of the region. Cold War big power politics gave way to a diplomacy centred on the Association of Southeast Asian Nations (ASEAN).This study is the first written based on the records of the Ministry of Foreign Affairs of Singapore, a key player in the complex diplomatic maneuvering of the period.