This book illuminates two familiar phenomena – diplomacy and the Commonwealth – from a new and unfamiliar angle: the atypical way in which the Commonwealth’s members came to, and continue to, engage in official relations with each other. This innovative and wide-ranging study is based on archival material from four states, interviews and correspondence with diplomats, and a wide range of secondary sources. It shows how members of an empire found it necessary to engage in diplomacy and, in so doing, created a singular, and often remarkably intimate, diplomatic system. The result is a fascinating, multidisciplinary exploration of the evolving Commonwealth and the way in which its 53 members and Ireland conduct diplomacy with one another, and in so doing have contributed a distinctive terminology to the diplomatic lexicon.