Despite its age, Lions's book is still considered an excellent commentary on simple, high quality code.

Lions's work was most recently reprinted in 1996 by Peer-To-Peer Communications,[6] and has been circulated, recreated or reconstructed variously in a number of media by other parties.

UNSW had obtained UNIX source code in 1975, in response to Ken Robinson's 1974 query to Dennis Ritchie at Bell.

[7] Bell Labs was a subsidiary of AT&T, due to the 1956 Consent Decree AT&T was not permitted to conduct business in any other field hence couldn't sell the software, though it was required, paradoxically, to license its inventions, such as Unix and the transistor.

[8] When AT&T announced UNIX Version 7 at USENIX in June 1979, the academic/research license no longer automatically permitted classroom use.

[citation needed] Other follow-on effects of the license change included Andrew S. Tanenbaum creating Minix.

As Tanenbaum wrote in Operating Systems (1987): When AT&T released Version 7, it began to realize that UNIX was a valuable commercial product, so it issued Version 7 with a license that prohibited the source code from being studied in courses, in order to avoid endangering its status as a trade secret.