Covering the efforts of the United States from 1945 to September 1959 to wrestle with the unknown ramifications of space, this history includes both the civilian and military activities. An Air Force History of Space Activities presents a more detailed treatment of information published in 1960 under the title of Threshold of Space, 1945-1959. Other monographs on this subject include The Air Force in Space, 1959-1960, and (in draft) a sequel for fiscal year 1961. The author of this history begins with the work of the early pioneers in rocketry, the first satellite feasibility studies by the military, and the relationship of the ballistic missile to the space vehicle. He reviews the Russian and U.S. space programs between 1945 and 1957, during which efforts were made to create space law and the United States chose to pursue a space-for-peace policy. The conservatism of policy makers raised obstacles, but there were space projects, some of them under the Air Force. After the shock of Sputnik I, the reshaping of policy resulted in the establishment of ARPA in the Department of Defense and NASA as the civilian space agency. The authors tells of ARPA's supremacy over the military services in 1958; its loss of control to NASA in October 1958; NASA's activities from then until July 1959; the position of the Air Force after losing out to both ARPA and NASA; and the Air Force's determination to cooperate with NASA, through research, development, and the use of its facilities. Within the DoD in 1959, authority for space research and development was transferred from ARPA to DDR&E, interservice tension mounted, the Air Force struggled to regain lost projects and objected to Navy's appeal for a military space command, and the tide turned for the Air Force when the Secretary of Defense decided in September to give to it the responsibility for the development and launching of all DoD space boosters and for management of Sentry, Midas, and Discoverer.