Britons played a central role in creating the administrative architecture and normative foundations of the UN. This chapter examines the international lives of Britons who worked at the United Kingdom Mission to the UN and the UN Secretariat. It outlines the challenges of writing histories of international civil servants, as their professional lives are often absent from traditional archives. The chapter then presents case studies on British officials’ relations with the UN’s first two Secretaries-General (Trygve Lie and Dag Hammarskjöld), UN public diplomacy, the opportunities and obstacles British women faced working in the Secretariat, and the UN’s early recruitment strategies.