Statins are well-known drugs to lower cholesterol levels and play an important role in the prevention of cardiovascular diseases. They inhibit hydroxymethylglutaryl-coenzyme A (HMGCoA) reductase, an enzyme that plays a central role in the production of cholesterol in the liver. Despite the growing experience in the use of statins, it is still difficult to predict the individual patient response in term of efficacy and possible adverse effects. This book discusses several medical uses for statins. It also discusses the mechanisms of action and clinical outcomes of using statins.