This book is about peace and security in the Asia-Pacific: it critically reviews various perspectives on peace and security in the region and seeks to determine whether any of them has now emerged as the winner in the struggle for hegemony. If none has, it may be wise for us to aim at building innovative theories based on the strengths of existing theories. As shall be discussed in this introduction, the study of peace and security is not only about the actual use or threat of force and the prevention of war, but also about the causes, consequences, and control of insecurity said to be rooted in various sources of threat to humans, their values, their agencies, and their environment, as well as about possible cures. Security as a concept is essentially contested and has become increasingly contestable. This conceptual challenge has the advantage of opening space for debate, but this book will make the case that, in the end, theoretical eclecticism offers the most promising perspective for the emerging policy agenda of building a regional security community during the 21st century.