As the National Aeronautics and Space Administration (NASA) celebrated its 50th anniversary in 2008, historians as well as scientists and engineers could look back on a record of accomplishment. Much has been written about the evolution of NASA's multifaceted programs and the people who carried them out. Yet much remains to be done, and we hope this publication will facilitate research in this important field. As an active internal function, NASA history also marks its 50th year in 2009. Aware of the historic mission on which it was embarking, NASA hired its first Chief Historian, Eugene M. Emme, in 1959. Emme remained on the job until 1978 and was the first of an unbroken line of NASA Chief Historians that included Monte D. Wright (1978-82), Sylvia Fries (1983-90), and Roger D. Launius (1990-2002). These individuals also served as Directors of the History Office at NASA Headquarters. As is evident from this publication, the various NASA Centers also carry out historical and archival functions. Research in NASA History describes the efforts of NASA to capture and record the events of its past and to make that past accessible to NASA personnel, the historical community, and researchers. It describes the research opportunities and accomplishments of NASA's Agency-wide history program. It also offers a concise guide to the historical documentary resources available at NASA Headquarters in Washington, DC; at NASA facilities located around the country; and through the federal records systems.