Abstract: How could one explain and characterize relative peace, security and prosperity in Northeast Asia (NEA) for the last two decades? What have we missed out theoretically in terms of seeing the then future of NEA? The dissertation challenges the prevailing pessimistic arguments about NEA security by criticizing their analytical failure to assess the progressive trends of regional interactions. In this vein, the dissertation re-characterizes the 17 years of the Post Cold War in the region as the surprising peace where regional states have achieved a progressive, relatively well-coordinated, cooperative, and prudent regional order. This dissertation provides a new framework of explaining NEA's regional order throughout the Post Cold War period. I argue that many different stimuli at structural level occurred for the last 17 years in NEA. But I also find the persistence of such ideas as war aversion, stability for development and regional prosperity throughout the region. And the overall outcome in Northeast Asian for the last 17 years is the avoidance of major harm and the progressive development of regional order. In order to explain the progressive regional order in NEA, I develop an analytical construct, Vision of Regional Order (VRO), to account for the unfolding of regional interactions for the past 17 years from a phenomenological approach. A VRO is states' expectation and understanding about what constitutes suitable behaviors towards neighboring states based on historical memories, perceived threat and perceived economic opportunity. Each VRO provide insights into behavioral disposition, which I call a vector or orientation of the major policy behaviors. I examine the four empirical cases -- the end of the Cold War, the 94 North Korean nuclear crisis, the 97 Asian Financial Crisis, the 2001-5 historical disputes. I find that the goals and preferences of NEA states have affected patterns of regional interactions and produced the surprising peace in the region. Regional orders are products of layers of multiple interactions by deliberately chosen strategies by regional states who implement their visions for the optimal regional order. This means that configurations of regional security dynamics are consciously pursued by states.