Studies conducted by the Institute of Medicine have demonstrated a serious gap between what the American health care system provides and its full potential. This results from a substantial amount of overuse, underuse, and misuse of health care. An Institute of Medicine (IOM) publication focusing attention on medical errors--To Err is Human: Building a Safer Healthcare System--galvanized the public and private sector as well as the professions to strive for building a safer health care system. In its report, Crossing the Quality Chasm: A New Health System for the 21st Century, the IOM's committee visualized a series of aims and rules for the health care system that would propel it successfully into the 21st century. Multidisciplinary professional teams should provide care for an increasing portion of the population (now about 40%) who have one or more chronic illnesses. Since 20 conditions account for 80% of America's health care costs, the author recommends that a special focus be placed upon 15 of these conditions to systematically improve the quality of care over the next five years. Information technology offers important opportunities to improve patient safety and contribute to better and continuous improvement of quality. The elimination of written clinical notes by the year 2010 is an achievable objective. These developments require medical educators and health professionals to move from a 20th-century paradigm of the physician who was in solo practice, held autonomy as a central value, prided himself or herself upon continuous learning and the acquisition of new knowledge, and laid claim to infallibility when confronting patients and colleagues. The 21st-century paradigm is that of physicians who understand teamwork and systems of care in which they can provide leadership. Group practice, both virtual and real, will allow the support of information systems, the collection of evidence about care, and efforts for continuous quality improvement. Fallibility should be replaced by an approach to multidisciplinary problem solving, and the acquisition of knowledge must be associated with the commitment and understanding of the need for change.