GREAT progress has been made over the past 30 years in identifying cardiovascular risk factors and in developing and implementing measures to correct them. The Adult Treatment Panel of the National Cholesterol Education Program developed guidelines in 1988 that identified low-density lipoprotein (LDL) as the major atherogenic lipoprotein and high levels of LDL cholesterol (LDL-C) as the primary target for cholesterol-lowering therapy. Since these guidelines were developed, the scientific database has significantly expanded. Genetic investigations into familial dyslipidemias, advances in molecular biology, animal experiments, human observational studies, lipid metabolic studies, epidemiologic data, and the results of interventional clinical trials looking at mortality, cardiovascular end points, and angiographic changes in atheromatous lesions have created interest in further examination of the role of high-density lipoprotein cholesterol (HDL-C) and triglycerides (TGs) in the pathogenesis of coronary artery disease. To address these questions, the National Heart, Lung, and Blood Institute and the Office of