The introduction of cortisone as a therapeutic agent stimulated chemical researches that have resulted in the commercial production of this drug and in a study of related steroidal agents. Part 1 of this volume summarizes the work on the synthesis and chemistry of adrenocortical steroids, and part 2 summarizes their fate in the body. Part 1, including papers by Fieser, Barton, Henbest, Heusser, Reichstein, Djerassi, Hirschmann, and other eminent workers in this field, is primarily of interest to chemists; part 2 concerns the biological aspects of the subject and will prove of greater interest to medical readers. Some of the subjects discussed are the biogenesis of the steroids, by Hechter; enzymatic factors, by Samuels; in vitro synthesis, by Dorfman; and corticosteroid metabolism in man, by Pincus. Although much remains to be done before we will know which steroids are elaborated by the adrenal and the factors controlling their secretion, much