The Agricultural Economics Society (AES) celebrates its centenary in 2026. This book tells the story of its history, and the people and events that have been part of that history, including Keynes, Attlee, Arthur Lewis, the 1947 Agriculture Act and Brexit. None of the other UK-level institutions created in the 1910s and 1920s to encourage studies in agricultural economics have survived. Thus the AES provides a unique lens through which to view continuity and change in the subject, and in the profile and work of its members employed in academia, government and industry. The book explores the challenges encountered by the AES's founding pioneers, and explains how their successors have sustained the Society's contribution to agricultural economics over the long run. The text draws on material from dozens of archives and interviews. It takes us through a hundred years of agricultural and applied economics including the founding of the AES, its existence during the Second World War and its expansion in the following decades. Later chapters consider other milestones and contexts in which the AES has adapted and evolved, such as the emergence of the internet. This book will be of interest to agricultural economists in the UK and beyond, and to all those interested in the development of the subject.