When I was first approached by O'Reilly to propose new covers for their books, I was immersed in the VAX/VMS world of Digital Equipment Corporation. I had heard of UNIX, but I had a very hazy idea of what it was. I had never met a UNIX programmer or tried to edit a document using vi. All of the terms associated with vi, sed and awk, uucp, lex, yacc, curses, to name just a few, sounded to me like words that might come out of a popular game called "Dungeons and Dragons." I developed a mental picture of the UNIX programmer as a "Dungeons and Dragons" player. As I started to look for imagery for the book covers, I came across some wonderful wood engravings from the 19th century. The strange animals I found seemed to be a perfect match for all those strange-sounding UNIX terms, and were esoteric enough to appeal to what I believed the UNIX programmer type to be.
-- Edie Freedman, Origin of Species: A History of O'Reilly Animals, 04/01/2000