Cholesterol is a soft, waxy substance found among the lipids (fats) in the bloodstream and in all your body's cells. It is transported to and from the cells by special carriers called lipoproteins. This book focuses on the two main types of lipoproteins- low-density lipoprotein (LDL) and high-density lipoprotein (HDL). LDL is the major cholesterol carrier in the blood. If too much LDL cholesterol circulates in the blood, it can cause atherosclerosis and/or clotting. HDL is known as "good cholesterol" because a high HDL level seems to protect against a heart attack. About one-third to one-fourth of blood cholesterol is carried by HDL. This book focuses on ways to reduce LDL-cholesterol levels, and therefore reduce the risk of serious health problems. Other factors that affect cholesterol levels, such as cigarette smoking and diabetes, are looked at as well. Different treatments, such as pharmacological therapies for high or low cholesterol levels are also examined.