"Why is a book that weaves together histories of heart care, a celebrated medical center, and specialization important? And why should it interest general readers as well as health care professionals, historians, social scientists, and policymakers? First of all, most individuals living in industrial countries have or will develop cardiovascular disease during their lifetimes. And most of them have already seen coronary heart disease alter or end the lives of family members and friends. Despite astonishing developments in diagnosis and treatment in recent decades, cardiovascular disease still kills more Americans than any other cause. Its economic implications are staggering. In the United States alone, medical costs and productivity losses related to cardiovascular disease are approaching $500 billion annually. ... Second, the Mayo Clinic is the world's oldest and largest multispeciality group practice. There is value in understanding why this institution has been a national leader in health care since the early twentieth century. ... Specialization is the book's third major topic. I agree with historian 's assertion that "specialization is the fundamental theme for the organization of medicine in the twentieth century." ..."