Pollution, resource depletion, habitat management, and climate change are all issues that necessarily transcend national boundaries. Accordingly, they and other environmental concerns have been a particular focus for international organizations from before the First World War to the present day. This volume is the first to comprehensively explore the environmental activities of professional communities, NGOs, regional bodies, the United Nations, and other international organizations during the twentieth century. It follows their efforts to shape debates about environmental degradation, develop binding intergovernmental commitments, and—following the seminal 1972 Conference on the Human Environment—implement and enforce actual international policies.