Source : Free On-Line Dictionary of Computing

Lions Book
     
         "Source Code and Commentary on Unix level 6", by
        John Lions.
     
        The two parts of this book contained the entire source listing
        of the {Unix} Version 6 {kernel}, and a commentary on the
        source discussing the {algorithms}.  These were circulated
        internally at the {University of New South Wales} beginning
        1976-77, and were, for years after, the *only* detailed kernel
        documentation available to anyone outside {Bell Labs}.
        Because {Western Electric} wished to maintain trade secret
        status on the kernel, the Lions book was never formally
        published and was only supposed to be distributed to
        affiliates of source licensees (it is still possible to get a
        Bell Labs reprint of the book by sending a copy of a V6 {source
        licence} to the right person at {Bellcore}, but *real* insiders
        have the UNSW edition).  In spite of this, it soon spread by
        {samizdat} to a good many of the early Unix hackers.
     
        {(http://www.peer-to-peer.com/catalog/history/lions.html)}.
     
        In 1996 it was reprinted as a "classic":
     
        [John Lions, "Lions' Comentary on UNIX 6th Edition with Source
        Code", Computer Classics Revisited Series, Peer-to-Peer
        Communications, 1996, ISBN 1-57398-013-7].
     
        [{Jargon File}]
     
        (1997-06-25)