Two great books about the LOCKHEED SR-71 Blackbird and the people who built them and flew them.  LOCKHEED BLACKBIRD, BEYOND THE SECREC MISSIONS by Paul Crickmore.   Plus LOCKHEED'S SR-71 FAMILY, A-12  F-12  M-21  D-21  AND SR-71 by James Goodall and Jay Miller.  Both book in very good condition.  Fascinating!