[X-15]. CROSSFIELD, SCOTT. Always Another Dawn. Cleveland, 1960. The story of the X-15 by the first man to fly it -- CAIDIN, MARTIN. X-15, Man's First Flight into Space. New York, 1959. A concise history on the X-15 -- X-15, Research at the Edge of Space, EP-9. 1964. NASA's role in this joint NASA and U. S. Air Force program -- two NASA 12 page picture booklets on the X-15 -- 50 black and white NASA press photographs on X planes, the majority on X-15 preparations, flights, and pilots, including Neil Armstrong. (55)