This book is a contribution to the debate about the advisability and feasibility of elevating the rank of the chief of the National Guard Bureau (CNGB) from that of three-star to four-star general. The book aims to shed light on the debate by examining the primary duties and responsibilities of a number of four-star billets, including the chairman and vice chairman of the Joint Chiefs of Staff; the unified and specified combatant commanders; the military service chiefs and vice chiefs; the commander, U.S. Forces Korea; and the deputy commander, U.S. European Command. The book also examines various categories of three-star billets to provide a basis for assessing whether the job of the CNGB significantly exceeds the typical three-star billet in responsibilities and scope. The book proposes that a subset of four-star billets exists that might make for a more fruitful comparison with the CNGB position than the frequently used position of military service chief of staff. For example, a more apt comparison might be between the CNGB position and the four-star commanders of the so-called "major commands" into which the larger military services, e.g., Army and Air Force, are divided. Most of the four-star major commands are functional commands, providing support services, such as training and materiel development, to the military services to facilitate their provision of combat-ready forces to the armed forces' joint warfighting organizations. Being less all encompassing in their responsibilities than an entire military service, the major commands do not as obviously outstrip the National Guard Bureau in the kinds of services the Guard provides to the U.S. Armed Forces."