AVOLUMINOUS literature bears witness to the intense interest and attention centered on the pituitary gland, and to the position of prime importance that it occupies among the endocrine glands. Such notoriety, though perhaps justified, has introduced many divergent opinions with sufficient confusion to distract the interest of the average reader from certain practical data relating to pituitary disorders. It is not difficult to understand how this situation has evolved: 1. Conclusions based on animal work have been too freely transposed and applied to human beings. 2. The tools used in studying pituitary function, especially in man, have been notably crude. 3. Many pituitary hormones employed clinically have been impure, of varying potency and quite unpredictable in the response which they elicit. 4. Inaccuracies have been perpetuated by adherence to historical precedent. Cachexia often is still regarded as a sine qua non of destruction of the anterior pituitary, probably because it was mentioned in the early descriptions of Simmonds' disease. 5. The diagnosis of endocrine disease has often been based on flimsy evidence. Thus, to some, every fat child with girdle obesity and small external genitalia becomes an instance of Fröhlich's syndrome, and every woman with menstrual irregularity has a primary pituitary endocrinopathy.