Internal medicine physicians are specialists who apply scientific knowledge and clinical expertise to the diagnosis, treatment, and compassionate care of adults across the spectrum from health to complex illness. Internists are sometimes referred to as the “doctor’s doctor,” because they are often called upon to act as consultants to other physicians to help solve puzzling diagnostic problems. Although internists may act as primary care physicians, they are not “family physicians,” “family practitioners,” or “general practitioners,” whose training is not solely concentrated on adults and may include surgery, obstetrics and pediatrics. General internists handle the broad and comprehensive spectrum of illnesses that affect adults, and are recognized as experts in diagnosis, in treatment of chronic illness, and in health promotion and disease prevention – they are not limited to one type of medical problem or organ system.