one of the most important works in the development of computer science was the "lions book". written by an austrailian computer scientist - john lions - it included the complete source code of the 6th edition of the unix kernel, as it was developed by bell labs. originally used as teaching materials for courses that lions taught, it spread via photocopy to many folks learning unix and just coding in the 70's. with the release of the 7th edition of the unix kernel, att/bell labs realized the huge commercial potential of unix, and removed their permission for the source code to be disseminated outside their labs, causing the lions book to become "banned literature". it spread napster-esque via photocopier across the world, and is considered one of the most photocopied works ever written. an interesting consequence of att's decision was that teaching unix in universities became less common. by revoking the academic rights to disseminate the kernel source code, they made it less attractive to the developing computer science curricula at universities around the world to teach it, and other computing concepts took its place. att really dropped the ball here. all one has to do is look at the popularity and prevalence of "c" above so many of its contemporaries, even now, as a computer language to get an idea of the influence in computing att/bell labs had in the beginning (they developed the original "c" syntax, it's name derived from the fact that this was their 2nd attempt at a usable language, after "b", named after bell labs). one has to wonder what would have been the outcome had att not revoked the rights to the 6th edition unix kernel source code. the entire face of computing would have changed - unix was way more advanced and powerful, obviously, than any of the existing crap that served as OS's in the 70's, and much like c took precedence over most other computing languages starting in the 80's, unix could have done the same thing, almost 30 years ago. the fact that unix is still around at all is a testament to its versatile design. if it had remained effectively academically "open source" from the beginning as it was, there's no telling the impact that would have had on computing.