The 1975 Apollo-Soyuz Test Project (ASTP) was the first joint U.S.-Soviet space flight, in which teams from the two nations met in orbit to test an international docking system and conduct both collaborative and independent studies. Although primarily a symbol of international goodwill, the mission provided useful experience for future cooperative ventures between the two nations. This authorized NASA history features many fascinating interviews with participants as well as firsthand observations of ASTP activities. Because details of the Soviet space program remained shrouded in secrecy during the ASTP, the story is told from the American perspective. No scientific background is necessary to appreciate the narrative, which focuses on the participants' working relationships rather than the technical aspects of their jobs. Starting with the early years of the Cold War competition, it traces the formation of an alliance between NASA and Soviet Academy engineers in developing a test project, training the crew, and the triumphant flight. Eighty-six pages of photographs include twelve full-color pages with images of Earth from space. Formerly a historian at NASA's Johnson Space Center, Edward Clinton Ezell is a curator of military history at the Smithsonian's National Museum of American History. Linda Neuman Ezell is a historian at NASA Headquarters.