This book offers a micro-global history of humanitarianism and medical care during the ‘long’ Second World War, which challenges the traditional and Eurocentric chronological boundaries of 1939/1945. It takes as its starting point the Japanese invasion of Manchuria in 1931, which led to the progressive dislocation of the League of Nations, with the Japanese, German and Soviet departures in the 1930s. It ends with the termination of the Korean War in 1953, and the subsequent dismantlement of the first United Coalition and UN Peace enforcement operation. It considers the slow, messy and ambivalent transformation of humanitarian actors’ relations to the suffering of distant others through a study of humanitarian encounters, practices, spaces and affects. Paying close attention to a variety of actors, such as French colonial doctors, Swiss ICRC delegates, Egyptian relief workers, Chinese-style physicians, Peruvian and Ecuadorian nurses or American member of the Unitarian Service Committee, the book provides a more holistic story of humanitarianism.