Throughout history, diseases of the heart have captured the concern and interest of investigators. Ancient Greek and Roman physicians observed the serious and often fatal consequences of heart disease. But effective treatment for heart disease was limited to rest and painkillers until the eighteenth-century discovery of the therapeutic properties of the foxglove plant, whose dried leaf is still used to make the medicine digitalis.

While the heart was once considered a part of the body that could never be improved surgically, the twentieth century has seen a revolution in surgical treatment for heart disease. Blocked coronary arteries can be bypassed using new tissue and failing hearts can be transplanted. Yet heart disease remains the primary cause of death in the United States. Preventive health measures, such as improved diet and regular exercise, have become fundamental tools in the battle against heart disease.

In the twentieth century...