Lions Book

Lions Book n.  "Source Code and Commentary on UNIX
   level 6", by John Lions.  The two parts of this book contained (1)
   the entire source listing of the UNIX Version 6 kernel, and (2) 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 license 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.