The Navy has put forth a new construct for its strike forces that enables more effective forward deterrence and rapid response. A key aspect of this construct is the need for flexible, adaptive command, control, communications, computers, intelligence, surveillance, and reconnaissance (C4ISR) systems. To assist development of this capability, the Navy asked the NRC to examine C4ISR for carrier, expeditionary, and strike and missile defense strike groups, and for expeditionary strike forces. This report provides an assessment of C4ISR capabilities for each type of strike group; recommendations for C4ISR architecture for use in major combat operations; promising technology trends; and an examination of organizational improvements that can enable the recommended architecture.