In 1920 Frederick Allen described the state of hypertension research as follows: The great importance of arterial hypertension or the conditions associated with it, as a widespread and apparently increasing cause of disability and death, is a self-evident incentive to investigation. At the same time it must be recognized that our knowledge of the subject is in a very confused state, as respects its phases of etiology, mechanism and treatment. Just as with diabetes, the literature contains almost every conceivable variety of opinions and suggestions. The first task of an investigator to choose is what seems significant and valuable among this mass of conflicting material, and the second is to build concrete facts with accurate methods in a clinical field which is still largely a morass of tradition and imagination. One cannot help but wonder whether we are any better off today. Although numerous treatments to lower arterial pressure exist, we are still searching for an accepted rigorous explanation for the etiology of primary hypertension. A brief review of the clinical literature from 100 years ago reveals an active debate on the nature of the relationship between arteriosclerosis and hypertension, and discussions on the role of the splanchnic nerves and circulation. Primary treatments were prescription of diuretics, exercise, and eating in moderation. The role of the kidney was debated, and restriction of salt was a suggested but controversial treatment.