Cargill Hall is Emeritus Chief Historian of the National Reconnaissance Office (NRO), an intelligence arm of the Department of Defense. Previously he served as Chief of the Contract Histories Program in the Air Force History Support Office, as Chief of the Research Division and concurrently Deputy Director of the Air Force Historical Research Agency, and as a historian at Headquarters Military Airlift Command and Headquarters Strategic Air Command. Still earlier he served as historian at the Jet Propulsion Laboratory, California Institute of Technology, for the National Aeronautics and Space Administration. He is the author of Lunar Impact: A History of Project Ranger (Washington, D.C.: NASA/GPO 1977), and is the editor, among other volumes, of Case Studies in Strategic Bombardment (Washington, D.C.: Air Force History and Museums Program, 1998); with Jack Neufeld, the U.S. Air Force in Space (Washington, D.C.: Air Force History and Museums Program, 1998); and Lightning Over Bougainville: The Yamamoto Mission Reconsidered (Washington, D.C.: Smithsonian Institution Press, 1991). Among his most recent contributions in the open literature are "The Evolution of National Security Space Policy and Its Legal Foundations in the 20th Century," Journal of Space Law, Vol. 33, No. 1, 2007, and, with Richard Smith, Five Down, No Glory (Annapolis: Naval Institute Press, 2011). Hall is a member of the International Academy of Astronautics and the International Institute of Space Law.