Deliberative democracy has been one of the main games in contemporary political theory for two decades, growing enormously in size and importance in political science and many other disciplines. This handbook takes stock of deliberative democracy as a research field, in philosophy, in various research programmes in the social sciences and law, and in political practice around the globe. It provides a concise history of deliberative ideals in political thought and discusses their philosophical origins. The book locates deliberation in political systems with different spaces, publics, and venues, including parliaments, courts, governance networks, protests, mini-publics, old and new media, and everyday talk. It engages with practical applications, mapping deliberation as a reform movement and as a device for conflict resolution, documenting the practice and study of deliberative democracy around the world and in global governance.