From the manual: Contractors have always accompanied our armed forces. However, the increasingly hi-tech nature of our equipment and rapid deployment requirements have significantly increased the need to properly integrate contractor support into all military operations. Recent reductions in military structure, coupled with high mission requirements and the unlikely prospect of full mobilization, mean that to reach a minimum of required levels of support, deployed military forces will often have to be significantly augmented with contractor support. As these trends continue, the future battlefield will require ever increasing numbers of often critically important contractor employees. Accordingly, commanders, staffs, and soldiers must be more familiar with how to plan for and use contractors effectively. This manual, along with an established, formal training program, provides the foundation upon which the Army can promote contractors on the battlefield education. Field Manual 3-100.21 (100-21) addresses the use of contractors as an added resource for the commander to consider when planning support for an operation. Its purpose is to define the role of contractors, describe their relationship to the combatant commanders and the Army service component commanders, and present their mission of augmenting operations and weapon systems support. This manual is intended for commanders and their staff at all echelons, program executive officers/program managers, and others involved in the planning, management, and use of contractors in an area of operations. It is also a guide for Army contracting professionals and contractors in implementing planning decisions and understanding how contractors will be managed and supported by the military forces they augment.