In the 1960s and 1970s, rapidly growing environmental awareness and concern not only led to widespread calls for new policies, but also created unprecedented demand for ecological expertise. This led to novel challenges for advocacy groups such as the International Union for the Conservation of Nature, which had to navigate rival scientific approaches, Cold War politics, and decolonization in their efforts to integrate the study and protection of nature into international policymaking. This book reveals how, despite their vast scientific knowledge and attempts to incorporate socially relevant themes, experts inevitably struggled to make conservation a central part of environmental politics within intergovernmental organizations like the United Nations.