Quincy N Butler & Harris A. Simmons 
Combatant Commands in the U.S. Armed Forces [PDF ebook] 
Elements and Considerations

The Unified Command Plan (UCP) and associated Combatant Commands (COCOMs) provide operational instructions and command and control to the Armed Forces and have a significant impact on how they are organized, trained and resourced — areas over which Congress has constitutional authority. The UCP is a classified executive branch document prepared by the Chairman of the Joint Chiefs of Staff and reviewed and updated every two years that assigns missions; planning, training, and operational responsibilities; and geographic areas of responsibilities to COCOMs. This book provides information on the history, mission, and operational considerations of the UCP and COCOMs with a focus on current issues and considerations.