The BBC "Secret War" series and RV Jones' books are superb. I would recommend also reading his "Reflections on Intelligence" - it was written later and is slightly more philosophical. By that time Jones had been burned by bureaucrats - he compares his small efficient wartime office to the post-war bloat.

The BBC series is really good. They don't make documentaries like that anymore. The "Still Secret" episode on Enigma is easily the best coverage of how the system worked, was cracked and the organisation behind it. There is also an accompanying book, which has many more details.

>I think The "Battle of the Beams" is one development that gave us the basis for what we use so much now in general aviation.

Actually it started the other way around. The beams were based on pre-war blind landing Lorentz system.