In At the Edge of Space , Milton O. Thompson tells the dramatic story of one of the most successful research aircraft ever flown. The first full-length account of the X-15 program, the book profiles the twelve test pilots (Neil Armstrong, Joe Engle, Scott Crossfield, and the author among them) chosen for the program. Thompson has translated a highly technical subject into readable accounts of each pilot's participation, including many heroic and humorous anecdotes and highlighting the pilots' careers after the program ended in 1968.