In the past few years there has been a great upsurge of interest in the problem of essential hypertension. This has been stimulated by several comparatively recent advances, the most important being the demon- stration that many if not most of the cOInplications of hypertension can be prevented with adequate and effective medical treatment. Because of the extremely high prevalence of hypertension (roughly one in six or seven adults) effective preventive treatment will have a tremendous im- pact on national health and longevity. This new approach to the problem of hypertension differs markedly...