A doctor with special training in the diagnosis and treatment of medical emergencies. Emergency physicians typically work in hospitals with people who have been injured in accidents or who have become sick very suddenly with such conditions as a heart attack or unexplained fever. Emergency physicians practice emergency medicine, a specialty developed out of the wartime experiences of physicians and paramedics on the battlefield who invented procedures and techniques that have been adapted for use in hospitals. The fundamental goal o f emergency medicine is to save lives by beginning treatment as soon as possible, preferably in the first minutes after a serious injury or illness.