Blood pressure control is central to all bodily functions. There are many points in the multifaceted cybernetic system wherein hypertension may be produced. Hypertension is a 'young' disorder whose existence has been known for less than a century. It is not only extremely prevalent among every popula- tion, but also deleterious to the health of mankind. The more we understand about hypertension's harmful effects, the more urgent is the need for its effective control. The kidney is the central organ that controls vascular tone and body fluid volume; these two factors are dominant in...