This book bridges theory and practice to rethink the contested relationship between federalism and democracy, with a focus on South and Southeast Asia. Bringing together philosophy, law, political science, and area studies, it offers a fresh interdisciplinary perspective on power sharing, democratic governance, and federal design. The first part develops key concepts by examining the intellectual history of federalism and democracy, the normative role of participation, cooperative power sharing, and the rule of law. The second part turns to practice, analyzing federal country cases including India, Nepal, Pakistan, Malaysia, Indonesia, and Myanmar. These chapters address minority rights, subnational autonomy, citizen&s participation, and the tensions between federalism, democratization, and authoritarianism. By highlighting both opportunities and challenges, the book provides fresh insights into how federal systems can shape or undermine democratic representation, accountability, and innovative governance in diverse societies.