Fuller Albright (1900-1969) was acknowledged as the preeminent clinical and investigative endocrinologist of his day by many of his contemporaries, but his many achievements are all but unknown to the present generation of physicians. This article describes how he used his clinical knowledge and a few tools--the measurement of urinary 17-ketosteroid excretion and the administration of methyltestosterone--to elucidate the major hormonal functions of the adrenal cortex and to clarify the pathophysiology of the Cushing syndrome. In addition, in a tour de force of clinical reasoning, he predicted, 5 years before the event, the discovery of a hormone that would reverse the endocrinologic abnormalities of congenital adrenal hyperplasia. Fittingly, he and pioneer pediatric endocrinologist Lawson Wilkins were the first to treat this disease successfully with cortisone.