Examining the public information strategies employed by the League of Nations between 1919 and 1940, this book brings together international history, intellectual history and the history of communications to tell the story of how officials in Geneva planned for a new kind of public relations to underpin and strengthen the League's internationalist project. Drawing on multi-archival work and shedding light on the role played by journalists in international diplomacy, it follows in the footsteps of individuals who left promising careers to work for the League's information section and shape opinion on a global scale. Showcasing their vision for an open diplomacy and an informed international public, Seidenfaden shows how this was sought for and achieved against the politically charged backdrop of interwar Europe. Moving beyond the outbreak of WWII, it also shows the legacies that remained after the League was in hiatus, and many of its officials in exile. In doing so, this book reveals how public information strategies developed by the League were transferred into its successor organisation, the United Nations, which continues to shape our world today.