This is a personal story of a multinational research programme that, instead of explaining conflict, has sought to explain peace, and to gauge its quality and sustainability. The Uppsala Conflict Data Programme has shown a dramatic drop in East Asian battle deaths between the 1970s and ’80s, just as wars got worse in the rest of the world. Since 1989, East Asia has been exceptionally peaceful. The book recounts heated discussions over how to explain a regional transition to peace. Was it due to a changing power balance? The ASEAN Way? China’s ‘peaceful development’ doctrine? Growing economic interdependence? Or, as the author contends, a series of national priority shifts by powerful Asian leaders who prioritized economic growth and thus needed external and internal stability? The book deals with civil as well as international conflict, and discusses why Thailand, Myanmar and the Philippines have not yet achieved internal peace. The author recounts his debates with colleagues who find it difficult to accept that a region with several unresolved militarized disputes, still ongoing civil wars, rising arms expenditures, massive human rights violations, and high levels of domestic violence can be called ‘peaceful’. East Asia, they say, has just a ‘negative peace’ or relative absence of war. Tønnesson, who holds that a ‘negative peace’ has tremendous positive value, includes a discussion of how to predict its future – can China keep peace with its neighbours? A rare combination of detached analysis and personal narrative, the book examines developments in the world’s most important region while also telling the story of how researchers with different assumptions develop rival theories and predictions.