The interests which have motivated the investigators of renal hypertension may be resolved for convenience into two categories. Most of the workers have been interested in the contributions which the study of renal hypertension may make to our knowledge of the pathology of hypertension in man. But others, although fewer in number, have been no less energetic in their desire to relate the participation of the kidney in the elaboration of pressor substances to a possible endocrine role of this organ in the intact organism. Many practical attempts to relieve hypertensive symptoms have already resulted from the study of renal hypertension. But the physiological role of the apparently secretory power of the kidney is still largely undetermined. Much more work remains to be done to clarify this role and, once accomplished, the rational basis for hypertension therapeutics will be present.