This monograph examines the exercise of staff control by the chiefs of staff at those headquarters either fighting or supporting warfare at the operational level. It is important for those commanders tasked to plan for warfare at the operational level to have firm control of their staffs without becoming personally involved in details. To serve them in this role, they need strong chiefs of staff, who are qualified in the eyes of the commanders and the staffs. This monograph examines the evolution of staffs and of chiefs of staff to determine if staff control at the operational level generates consistent requirements for a chief of staff, and what qualities are expected of a chief of staff to successfully meet those requirements. It studies the contributions of Lieutenant General Walter Bedell Smith, Eisenhower's Chief of Staff during World War II, to the concept of what the chief of staff at the operational level of war is supposed to be, know, and do. Doctrine is examined to determine if there are any shortfalls which need to be addressed with respect to the duties and authority of the chief of staff. The monograph concludes that in order to execute proper control of joint and combined staffs and their functions, the current doctrine requires refinement in current staff arrangements to allow for greater staff flexibility in meeting requirements. Additionally, the approach to the authority granted the chiefs of staff should become permissive rather than restrictive, allowing them virtually to command the staff. Finally, those selected to serve as chiefs of staff must complement their commanders; each should be of the same service as his commander, and should perhaps be nominated for his position as chief of staff by his commander from a list of qualified candidates. In these ways, the commanders at the operational level of war will have chiefs of staff with whom they are more comfortable; who are more prepared doctrinally to assume the role; and who will maintain m