This volume reviews research on the metabolism of high-density lipoproteins (HDL) and their role in "reverse cholesterol transport." a process by which cholesterol returns from peripheral tissues to the liver and is eventually eliminated from the body. Coverage includes studies on the determinants of HDL structure, the metabolism of HDL particles in different clinical conditions, the molecular aspects of reverse cholesterol transport, the HDL receptor, the regulation of HDL binding, and the genetics of apolipoprotein A-I. Attention is given to findings on the role of the cholesterol ester transfer protein in determining plasma HDL levels and on the strong inverse relationship between HDL and plasma triglycerides. The contributors also describe dietary and pharmacological approaches to modulating HDL plasma levels or function.