The way in which blood pressure is controlled is not well understood. I offer as evidence the spirited debates among scientists that have occurred in the past and that will probably continue for some time to come. Consider also that hypertension is a disease of significant morbidity and mortality, yet in the majority of instances the cause of the pressure elevation is unknown. And further, the wide variety of antihypertensive drugs currently used, often without a full understanding of the mechanisms involved, suggests that we often know as little about what decreases blood pressure with antihypertensive therapy as we know about what increases pressure in the first place. This ignorance has fostered and probably justified extensive inquiries into outstanding problems of blood pressure control. The pace has quickened in the last one or two decades, and published reports germaine to the subject appear to be accumulating at an exponential rate. Hence, speaking for myself, the reviewer is faced with too little understanding and too much information.