This book is about how international actors compete for a ‘seat at the table’ in the management of international society and how that competition stratifies the international domain. It helps develop a theory of ‘international social closure’ to equip international relations (IR) to better capture these dynamics, explain why actors adopt particular strategies in their pursuit or maintenance of status positions, and understand how these things are significant in the maintenance of international order. This book examines how competition for inclusion in the management of international society has changed over time and what this means for contemporary politics by examining three different status groups throughout the history of the particular international society that has come to encompass the globe: the Family of Civilised Nations, the Great Powers’ club, and G-summitry (the G7 and G20). I argue that the same dynamics of social closure that operated during the globalisation of Western European international society continue to stratify international order today. 1