This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book examines the complex problems of the Korean peace process by focusing on two levels, that is, inter-Korean and international levels. It analyzes the Korean peninsula peace regime building as one of the essential conditions for achieving a peaceful unification of the Korean peninsula. The book discusses the significance of North Korea’s changes and examines its implications for the Korean peace process. It highlights North Korea’s behavior pattern from the ‘mercantile realism’ perspective. North Korea’s startling confession about its covert uranium enrichment nuclear weapons program has re-ignited the political debate in the United States, South Korea, and Japan about how to deal with North Korea. The book describes China’s concern over the Korean peace process by analyzing Beijing’s relations with both Pyeongyang and Seoul.