Probably no other organ of the body has quite captured the imagination of physicians and investigators or been so elusive in hiding its secrets as has the pituitary. At least, size for size, it outranks all other organs in these respects. The ancient view shared by Galen and Vesalius and depicted graphically in Vesalius de Fabrica (1543) held that the gland elaborated a secretion (pituita) for the lubrication of the nose. Later, under the influence of comparative embryology and the doctrines of evolution, the pituitary gland was relegated to the limbo of vestigial relics. An awakening took place with the publication of Pierre Marie's reports during the 1880's in which the anomalies of growth characterizing acromegaly were shown to be associated with a tumor or enlargement of the pituitary. The record of progressive discoveries of the role the pituitary plays in the body's development and economy has been exciting and