This project analyses how elite scientists involved in the Pugwash Conferences on Science and World Affairs (Pugwash) contributed to conflict moderation in the period 1957–1977. Arising from the Russell-Einstein Manifesto of July 1955, Pugwash brought together scientists from across ideological and political divides to confront the dangers of the nuclear arms race. Beginning in 1957, Pugwash sought to develop a distinctive transnational approach to disarmament centered on regular conferences. Powered by ideas about scientists’ special social responsibility, and claiming a “common language of science” and political neutrality, Pugwash sought to become a “strong force for peace”: as such, it was a bold experiment. Surviving difficult beginnings, Pugwash forged a novel role as a channel of east-west communication and, by the 1960s, was serving as an unofficial “back channel” between the blocs. In 1995, it was awarded the Nobel Peace Prize for its work. However, its transnational activities, roles and influence remain poorly understood. This project takes Pugwash in the two Germanys as a case study to explore its distinctive mode of operation. Situating its development here within the respective national scientific landscapes, it pays particular attention to the trust-building process between scientists and the use of trust as a resource. It asks how far “Pugwashites” in the Federal Republic and the GDR could transcend political differences and ideological ties in order to cooperate across the divide. It analyses their relationships with senior politicians and policy-makers in Bonn and East Berlin, and their influence within these circles. It also assesses the importance of the German groups within Pugwash as a whole, especially their role in repositioning the “German question” at the top of its agenda during the 1960s. Overall, this project aims to provide new insights into the experience of scientists operating at the intersection between science and politics and enhance understanding the diverse roles of scientists within the national security state during the early Cold War.