Hypertension is no more than an elevated arterial pressure and essential hypertension the term applied to those in whom elevated arterial pressure cannot be ascribed to a specific cause. The view that essential hypertension is a specific disease has been abandoned in favour of the proposition that blood pressure is a quantitative trait that is continuously distributed in the population in much the same way that height is. Thus, there is no natural point of separation of people into dichotomous groups with high or low blood pressure. Life insurance tables describing the link between arterial pressure and mortality show a continuous relationship that extends well into the normal range and the same is true for stroke, which is very strongly correlated with the level of blood pressure. A pragmatic solution is to classify as hypertensive those in whom treatment has been shown to be beneficial in reducing morbidity and mortality.