> the entire source code of PGP (yeah they put it in a book, don't know why)
Because PGP used keys larger than 40 bits, which meant if was classified as 'munitions' (!) under US export regulations. Zimmerman got around that by publishing the source code as a book, export of which is protected under the First Amendment. You were supposed to OCR it...
http://en.wikipedia.org/wiki/Pretty_Good_Privacy#Criminal_in...
There's also a lot of economics/sociology books on sale, so you can pick up esoteric things on a number of subjects. Just go, go, go.