Army Techniques Publication (ATP) 4-02.55 provides guidance to the medical commander, medical planner, and command surgeon at all levels of command in planning Army Health System (AHS) support for unified land operations. The AHS is a complex system of interrelated and interdependent systems which provides a continuum of medical treatment from point of injury or wounding through successive roles of medical care to definitive, rehabilitative, and convalescent care in the continental United States (CONUS), as required. Planning is an essential element which facilitates the successful accomplishment of the Army Medical Department (AMEDD) mission. The medical planner, by carefully applying AMEDD doctrine and principles, is able to provide the best possible AHS for all Army operations. The AHS provides support to forces deployed across the full range of military operations with its various operational arrangements. The AHS is a complex system of highly synchronized, interrelated and interdependent systems comprised of ten medical functions. It is a system of systems. The medical functions align with medical disciplines and specialty training with the capabilities required to provide state-of-the-art care to Soldiers regardless of where they are deployed or assigned. The functions include: medical mission command, medical treatment (area support), hospitalization, dental services, preventive medicine services, combat and operational stress control, veterinary services, medical evacuation, medical logistics, and medical laboratory.