This book examines British responses to disease during the Seven Years War with a particular focus on the role of the state and its relationship to the welfare of the armed forces. Alongside fiscal and logistical capability, British success required consistent and well-publicized attention to the welfare of troops to maintain manpower strength, support recruitment, and retain public support and public financing for the war. The strength and success of the British state during the war is shown to be dependent on its ability to secure public support through attention to troop welfare. This was accomplished by encouraging and supporting medical research, applying medical knowledge, and adapting to local conditions around the globe. The incidence of disease thus played a crucial role in the formation of strategy and policy; in turn, the war stimulated new ways of thinking about disease and medicine, particularly in colonial environments. By tracing how imperial warfare shaped the development of British medical expertise, this book highlights the central role that the British state played in shaping eighteenth-century medicine and scientific innovation. Not only did the discipline of tropical medicine have its roots in the war, but the experience of war provided naval and military medical practitioners with the opportunity for observation and experimentation. Moreover, wartime medical experience conferred authority and status on naval and military medical practitioners. Medicine became a form of expertise in the service of the British Empire, applied during campaigning and influencing both imperial policy and the nature of imperial authority.