South Korea provides an intellectual challenge in the fields of social movements and democracy in that intense mobilization and the strong influence of social movements have accompanied steady democratization for more than two decades, despite major theories having predicted otherwise. This book examines how social movements in previously authoritarian contexts evolve after democratic transition, using South Korea as a case study. It explores how democratic change influences the form of social movements, and how social movements affect the pace and direction of democracy in turn. It explains how South Korean social movements were able to attain strong political influence by focusing on four causal factors: the configuration of major political actors during the transition period, the relational dynamics among social movement groups, the relationship between social movements and institutionalized political actors, and the impact of transnational forces in the post-transition period.