International news-agencies, such as Reuters, the Associated Press and Agence France-Presse, have long been 'unsung heroes' of the media sphere. From the mid-nineteenth century, in Britain, the US, France and, to a lesser extent, Germany, a small number of agencies have fed their respective countries with international news reports. They informed governments, businesses, media and, indirectly, the general public. They helped define 'news'. Drawing on years of archival research and first-hand experience of major news agencies, this book provides a comprehensive history of the leading news agencies based in the UK, France and the USA, from the early 1800s to the present day. It retraces their relations with one another, with competitors and clients, and the types of news, information and data they collected, edited and transmitted, via a variety of means, from carrier-pigeons to artificial intelligence. It examines the sometimes colourful biographies of agency newsmen, and the rise and fall of news agencies as markets and methods shifted, concluding by looking to the future of the organisations.