This document summarizes the history of emergency medical services (EMS) systems from ancient times to the present. It describes early developments in pre-hospital care and transport during wars and the 19th century. Major advances in the 20th century included the development of CPR, defibrillation, trauma systems, and the establishment of EMS education and training standards. The document also outlines federal legislation and reports that established EMS systems and outlined essential components, including the 15 components defined in the 1973 EMS Systems Act and 10 elements from NHTSA in 1988. It concludes with ongoing challenges and issues facing EMS in the 21st century.