Historically, prolonged campaigns have been frequently lost or won because of the greater fitness of one of the combatant armies. In the twentieth century, infection was still a major problem, leading to withdrawal from Gallipoli, and the near defeat of the Allies due to malaria early in the Second World War’s Pacific campaign. Malaria emerged again as a major problem in the Vietnam War. The Australian Army Medical Corps, founded in 1901, learned from past medical experience. However, errors leading to significant morbidity did occur mainly in relation to malaria. These errors included lack of instruction of doctors sent to New Guinea with the Australian Force in the Great War, inadequate prophylactic measures against malaria in New Guinea early in World War Two, failure to perceive the threat of emerging resistant strains of malaria in the 1960s, and military commanders not fully implementing the recommendations of their medical advisers. Many Australian campaigns have taken place in tropical locations; a substantial amount of scientific work to prevent and manage tropical diseases has therefore been conducted by the Army Medical Corps’ medical researchers—particularly in the Land Headquarters Medical Research Unit and the Army Malaria Institute. Their work extends well beyond the military, greatly improving health outcomes throughout the world. This book recognises the efforts of both.