Henry E. Sigerist's paper on the history of dietetics covers the entire development of dietetics since the emergence of the human species. Originating in early man's food-seeking instinct, dietetics had become an empirical science by the time of the ancient Greeks. They stressed the dietetic treatment of illness and began to formulate numerous rules. Regimina sanitatis, manuals containing precise dietetic prescriptions for the maintenance of good health, were widely circulated in the Middle Ages. In addition to new impulses initiated by Paracelsus, the author emphasizes the clinical and experimental studies pursued, from the 17th to the 19th centuries, by such scientists as Thomas Sydenham, Justus von Liebig, Carl von Voit and Gustav von Bunge. The author concludes by pointing out that, despite enormous progress, more than one half of the world's population still suffers from malnutrition. For this reason, he regards the social application of dietetic findings as the most urgent task facing us in the future.