Few federal agencies have prospered as greatly in recent years as the National Institutes of Health, the research branch of the US Public Health Service. Every year, with uncommon enthusiasm, Congress approves larger and larger expenditures for the study of human disease. Already NIH has become the hub of an enormous research effort, and its program will probably continue to expand. The agency has grown so rapidly since the end of World War II that the prewar and wartime stages in its development are now almost forgotten. It was during the 1930's that NIH began laying the groundwork for its current research program. Before the end of World War II federal public health officials had formulated the objectives, worked out the basic organizational pattern, and gained the legislative authority for a great postwar medical. research effort. Their far-sighted policy, carefully calculated to advance the cause of federally sponsored medical research, made it possible for NIH to become the giant that it is today.