This ground-breaking volume shows that young people largely shape their own political development, and that to understand young people's political development, we must consider their political agency. Håkan Stattin explores the findings of an extensive longitudinal study of the political socialization of young people in Sweden from the ages of 13 to 28, which shows that, contrary to popular belief, it is not parents, peers, teachers or other key adults who are the primary agents in shaping young people's political development; it is their own self-directed political interest. Given that political interest is both an input and an output, the book examines how political interest affects young people's political interactions with their parents, and why young people and their parents perceive these interactions differently. It covers key issues such as the impact of political-interest-triggering events and civil unrest, the role of school and peers, parental involvement and the path from political interest to future political and civic engagement. Launching a new field of research internationally, this volume is essential reading for researchers, students, educators, and policy developers interested in young people's political and civic attitudes, engagement, communication, core values and the emergence of intrinsic political sophistication.