I'm reading a fun book at the moment about the true story of how the USAF had a squadron of MIGs for aggressor training there too...
Also, broader away from recent military skunk works is anything by Simon Singh, particularly The Code Book and Fermet's Last Theorum.
Blind Man's Bluff is good, as another poster suggests.
Another fun one is "The theory that would not die," about the history of Bayes rule.