Principles of EMS Systems, Third Edition provides EMS personnel with an overview of the organization and operation of an EMS system, both on a daily basis and in response to large-scale events, including terrorist and weapons of mass destruction incidents.  This book explores the role the medical director plays in EMS and discusses the importance of medical oversight and accountability.  By focusing on the collaborative interaction of EMS, police, and fire professionals, along with emergency physicians, emergency departments, and hospitals, this resource provides a framework for how these different groups must work together to ensure the emergency medicine/health care safety net does not fail when it is needed the most.