It is often assumed that only sovereign states can join the United Nations. But this was not always the case. At the founding of the United Nations, a loophole drafted by British statesmen in its predecessor organisation, the League of Nations, was carried forward, allowing colonies to accede as member-states. Colonies such as India, Ireland, Egypt, and many more were afforded a tokenistic representation at the League in Geneva during the interwar years, decades before their independence. Thomas Gidney’s An International Anomaly unites three geographically distinct case studies to demonstrate the evolution of Britain's policy from a range of different viewpoints, exploring how this policy came into being, and why it was only exploited by the British Empire. He argues that this membership shaped colonial norms around sovereignty and international recognition in the interwar period and to the present day. Thomas Gidney is a postdoctoral researcher in international history and politics at the Geneva Graduate Institute. Lucas Tse is an Examination Fellow at All Souls College, Oxford.