This book presents the most complete set of analytical, normative, and historical discussions of majority decision making to date. One chapter critically addresses the social-choice approach to majority decisions, whereas another presents an alternative to that approach. Extensive case studies discuss majority voting in the choice of religion in early modern Switzerland, majority voting in nested assemblies such as the French Estates-General and the Federal Convention, majority voting in federally organized countries, qualified majority voting in the European Union Council of Ministers, and majority voting on juries. Other chapters address the relation between majority decisions and cognitive diversity, the causal origin of majority decisions, and the pathologies of majority decision making. Two chapters, finally, discuss the counter-majoritarian role of courts that exercise judicial review. The editorial Introduction surveys conceptual, causal, and normative issues that arise in the theory and practice of majority decisions.