The purpose of this text is to present a comprehensive guide which can be utilized for training and indoctrinating regular and reserve Medical Department personnel with the many intricate problems connected with submarine medicine practice. An attempt has been made to assemble in this volume the highlights of latest developments and the accumulated knowledge and experience resulting from years of research and investigations. Much has been accomplished in this respect since 1917, the year organized studies in the medical problems of undersea warfare were first initiated, but recent ventures and developments in underwater military operations demand an even greater surveillance of the medical problems involved. For the medic officer interested in the solution of these many unsolved problems, submarine (underwater) medicine practice offers a most challenging and fertile field. Increasing cruising range and prolonged submergence of modern submarines, penetration of greater depths by the deep sea diver, and the expanding practice of underwater swimming demand continued research effort and a promise of rich rewards for the individual investigator. These discussions include personnel selection and assessment procedures, improvement of submarine habitability factors, solution of human engineering problems aboard submarines, submarine escape and rescue operations, and the medical aspects of all other undersea operational problems directed toward the improvement of the military effectiveness of the Submarine and Amphibious Forces. This book was originally published in 1956.