This interdisciplinary volume explores religious conversion and nonreligion in 20th-century Central and Eastern Europe, examining how emerging nations, empire inheritors, and socialist projects mobilized religious politics to manufacture consent while destabilizing the very communities they sought to control.Drawing on original archival research and fieldwork, the book analyzes the interdependence of collective and individual identities, integrating state-driven atheization into the study of conversion. It traces conviction-driven, coercive, strategic, and nonreligious shifts, situating them within broader processes of state formation, social engineering, and political power. Rich in empirical material, the volume offers conceptual tools and comparative frameworks to understand the entanglement of religion, nonreligion, and power during political upheaval.Intended for scholars and practitioners in history, religious studies, anthropology, sociology, political science, and related fields, this book provides valuable insights for those studying the dynamics of religion and nonreligion in politically complex contexts.