•What is a doctor? •A doctor is a medical specialist who treats patients. Doctors diagnose, treat, and advise people with illnesses, ailments, and injuries. Their many responsibilities include patient examination, collecting patient information, performing diagnostic tests, and directly treating diseases. For virtually every major organ system in the human body, there is a specific type of doctor. For example: ophthalmologist, dentist, cardiologist, rheumatologist, and dermatologist. •The origin of the profession can be traced back to more than 25,000 years ago when the first "healers" were found on cave paintings in the territory of modern France. The images showed people using plants for medicinal purposes. This is the first known example of medical knowledge transferred through tribes.