For the past eight years we have been privileged to witness a revolutionary transformation in the treatment of prostatic carcinoma through endocrine control, an advance based largely on the work of Charles Huggins. The physician has seen the original enthusiasm attendant on this discovery become tempered by the knowledge that the benefits were not universal, that the degree and duration of response were variable and that eventually most patients experienced relapse and subsequent death from the primary disease. The physician has been confronted with problems concerning the selection of the form of endocrine modification most efficacious for the particular needs of the patient, the designation of the most opportune time to institute therapy and the choice of secondary therapy once relapse has occurred. The answer to these and many other questions should be found in the clinical evaluation afforded this form of therapy by its use in thousands of patients