The Army is composed of both an Active Component (AC) and a Reserve Component (RC). The AC consists of soldiers who are in the Army as their full-time occupation. The RC is composed primarily of soldiers who serve part-time but who can be ordered to full-time duty. The Army's RC is made up of both the Army National Guard (ARNG) and the United States Army Reserve (USAR). AC/RC force mix refers to the distribution of units between the active and reserve components of the armed forces. This book discusses the AC/RC force mix, as well as the unit cost and readiness for the AC and RC.