The Union of International Associations (UIA) was founded in 1910, aiming to coordinate the relations and interests of international organizations across the world. Its long history makes it a prism through which to study the field of international organizations and its dynamics. Bringing together experts from fields including history, political science and international relations, architecture, historical sociology, digital humanities and information studies, International Organizations and Global Civil Society is the first scholarly book to cover both the UIA's early years and its more recent past. Key issues explored include the UIA's importance for the field of scientific internationalism, the relations between the UIA and other international organizations, and the changing position of the UIA when facing geopolitical challenges such as totalitarianism, the World Wars and the Cold War. This important book addresses a number of current scholarly concerns: the concept of "global civil society"; the development of international relations as a field of study; the investigation of transnational factors in modern and contemporary history; and the tracing of forerunners to the "information society". This volume sheds new light on the history of international cooperation in the 20th century. Breaking out of the mould of narrow institutional histories, the authors bring the UIA to life as a crucial element of the infrastructure of Brussels-centred internationalism, and one which provided the scaffolding for many international ventures.