Future physicians go to medical school after they complete college. Medical students learn about many different areas of medicine, including those designated as specialties. At the end of medical school, doctors choose the specialty in which they will have more education and eventually practice. Education in each specialty takes 3 to 7 years of a residency after medical school. Some medical specialties have subspecialties that require even more education and training. Since medical knowledge is so complex and advanced, most doctors limit their practices to their area of specialization. The September 5, 2007, issue of JAMA is a theme issue on medical education. This Patient Page is based on one previously published in the September 3, 2003, issue of JAMA.