The author provides an overview of command and control (C2) in 'common defence'. The approach is to show the linkage between the American people and operational performance of the U.S. military during combat. The Preamble to the Constitution and the basic definition of C2 stated in the Joint Chiefs of Staff (JCS) Publication 1 are used as the start point for the thesis. From this start point, a tracing of C2 in 'common defence' is conducted. These levels are hierarchical with a two-way vertical and horizontal flow of information. Low/high context and external transference are used to describe and trace the flow of C2 in 'common defence' through the hierarchical levels. The author documents the actual means of decision making, planning, directing, influencing, coordinating, and/or controlling the operational performance of the military force. Keywords: National security; Information systems; Command and control; Command control and communications; Command control communications and intelligence; Military thesis. (kt)