This document provides information about basic life support (BLS) including cardiopulmonary resuscitation (CPR). It defines BLS as an emergency procedure to recognize respiratory or cardiac arrest and use CPR to maintain life until the victim recovers or more advanced support is available. It describes the links in the chain of survival and emphasizes the importance of early access to care, early CPR, early defibrillation, and early advanced cardiac life support. The document also reviews anatomy, body systems, risks for cardiovascular disease, and what occurs in a heart attack.