IT is now well established that hypercholesterolemia is an important cause of coronary heart disease, and clinical intervention studies have demonstrated the therapeutic value of correcting hypercholesterolemia.^{1 , 2} The National Cholesterol Education Program has been instituted on the basis of these findings.³ From that ambitious program we can anticipate the development of progressively better methods of reducing plasma cholesterol levels and therefore even further decreases in mortality from coronary heart disease. However, no matter how successfully we deal with hypercholesterolemia, coronary heart disease will not disappear, because a high cholesterol level is by no means the only causative factor. At any . . .