The introduction explains the global-historical, interdisciplinary, and historiographical importance of this topic; sketches the history of decision-making in popular assemblies prior to the seventeenth century; and describes how the book will conceptualize and measure consensual and majoritarian forms of decision-making in the English House of Commons and the colonial lower assemblies. Majority decision-making is taken to be either natural or automatic in politics. This is short-sighted. The dominance of majority decision-making as a global standard for political decision-making is therefore something to be explained, not assumed. It is impossible, therefore, properly to address the promise and pitfalls of majority rule today without a history of its rise at the ready. This book is the first such history. It describes and explains the crucial moment in the majority’s global rise to power: its embrace by the elected assemblies of Britain and America in the age of the English, Glorious, and American Revolutions.