Science Diplomacy 1 is a vibrant research field: this is illustrated by the growing number of scholars who are exploring the field both by studying contemporary issues and reevaluating past conflicts and political negotiations. Coming not only from the ranks of historians, scholars from international relations, Science and Technology Studies, and science management, to name a few, are exploring the history of science and diplomacy. 2 Nevertheless, much is yet to be understood with respect to science and diplomacy's historical dimensions and the ways in which science and technology have become increasingly important devices in the administration of foreign affairs since the beginning of the Cold War. Founded in 2018, the Commission on the History of Science, Technology and Diplomacy 3 organized its first conference from 19-20 July 2019 at the Niels Bohr Archive in Copenhagen. The conference brought together researchers from several countries and various fields who explored the diverse history of science diplomacy as an endeavor, focusing especially on the actors involved. The papers presented at the conference described and analyzed how particular diplomats, scientists, and institutions used techno-scientific knowledge in their diplomatic efforts. This special issue bears the same title as the DHST conference and includes six of the papers presented in Copenhagen. As a diplomatic activity, science diplomacy refers to the practice of using science and technology in diplomacy to foster dialogue and cooperation between na