Doctrine provides a military organization with unity of effort and a common philosophy, language, and purpose. This manual discusses the organization and operations of the theater army headquarters, including its role as the Army Service component command (ASCC) to the geographic combatant commander (GCC) and the relationships between the theater army headquarters and the theater enabling commands. The manual also discusses theater army responsibilities for setting the theater, Title 10 functions and responsibilities, generally referred to as the combatant commander's daily operations requirements, as well as the operational employment of the theater army's contingency command post (CCP) to directly mission command limited types of operations. FM 3-93 serves as a guide for organizing the theater army headquarters and its command posts, for training the staff, and conducting operations as directed by the combatant commander. FM 3-93 has sixteen chapters and one appendix. Chapter 1 discusses the theater army's role as the ASCC and the joint context in which it operates. It discusses the theater army's responsibilities to support the combatant commander's theater campaign plan across the GCC's area of responsibility (AOR), referred to as the theater army's AOR-wide support responsibilities. It also discusses the theater army's role in theater opening, including reception, staging, onward movement, and integration (RSOI) of Army and joint forces provided to the joint force commander (JFC) in joint operations areas (JOA) opened within the AOR, and the theater army's dominant role in sustaining Army and joint forces, as directed, across the AOR. Chapter 1 also discusses the sustainment concept of support and the modification of responsibilities of the Army forces commander (ARFOR) within the JOA. Finally, Chapter 1 discusses the theater enabling commands (intelligence, sustainment, medical, signal, and aviation) and their command or support relationships with theater army and the ARFOR operating in JOAs within the AOR. Chapter 2 discusses how the theater army employs its CCP to support joint and combined training exercises and other theater security cooperation activities. It also discusses the direct mission command of limited (scale and scope) military operations within the AOR. Chapter 3 discusses the organization and functions of the theater army's main command post. Chapter 4 discusses the organization and functions of the theater army's CCP. Chapter 5 discusses the organization and functions of the headquarters and headquarters battalion, which provides administrative and sustainment support to the theater army headquarters staff. Chapters 6 through 14 discuss the organization and functions of the theater army command group, personal and special staff, and the warfighting functional cells (intelligence, movement and maneuver, fires, protection, sustainment, and mission command). Chapter 15 discusses the organization and functions of the theater army CCP, and its capabilities, limitations, and dependencies. Chapter 16 discusses the organization and functions of the theater army headquarters and headquarters battalion (HHB), including HHB sustainment support for the CCP when it deploys. The appendix explains doctrinal command and support relationships, and lists the Army Title 10 responsibilities. Tables A-1 through A-35 illustrate Army support to other Services and executive agent responsibilities. Although these responsibilities may be changed or amended over time, assignment of Service responsibility is based on the Service's capabilities. Thus, changes in lead Service responsibilities are infrequent."