This book develops a theory of political order explaining political change in Japan, China, South Korea, Taiwan, Vietnam, and North Korea. The book considers political change as the shaping of political order in a given polity where state authority is claimed and exercised by influential political forces. Authority relations among influential political forces are determined, enforced, legitimized, and moralized by the power structure among the political forces, effective political institutions, and prevalent political norms. The book investigates the setup of new states in East Asia over the national populations after the collapse of the Chinese Empire and Japanese Empire in the first half of the 20th century, East Asian Spring in the 1950s, the rise of Cold War regimes, decentralization of state authority and pluralization of polity organization in the 1980s and 1990s, and the emergence of two different types of political order in the early 21st century: a statist order in states on continental East Asia and a pluralist one in those offshore. The book advances a strong and original argument for the transformative role of power and authority structures in the simultaneous state formation and nation building in modern East Asian states, and offers a fresh perspective on contemporary East Asian politics, the explanation or interpretation of which has been dominated by those of liberal institutionalism and East Asian cultural traditionalism.