The properties and modes of action of both the vitamins and the hormones, and their interrelationships to each other as metabolic controlling agents, are easily accessible in this handbook. The book was written to alleviate the continued frustration experienced by many people, including myself, when attempting to obtain unitary, basic information on vitamins and hormones. Although many of the data are separately available, they are so scattered in many compendia, original research papers, and reviews that a small research project on each vitamin and hormone is required before most of the data can be placed in proper context and profitably used. This feeling of dissatisfaction was brought to a head when I recently presented graduate courses in Endocrinology and on Vitamins and Hormones, thus providing the stimulus for this book. Much of the material, and the general format of this volume were generated from lecture notes for the course on Vitamins and Hormones. It is hoped that this book will be of use to researchers and students in the various fields of life sciences, as well as to physicians, pharmacologists, nurses, and dietitians. Moreover, this book has sufficient content of semitechnical language to make it useful to the educated layman who might need ready information to guide him through the vitamin fads of the day, including rational meal and cooking selections, and to aid in understanding the hormone-related articles in various newspapers and magazines.