Ashby's book "Introduction to Cybernetics" (2003)
pespmc1.vub.ac.be
pespmc1.vub.ac.be
An Introduction to Cybernetics (1957) [pdf] - https://news.ycombinator.com/item?id=10372044 - Oct 2015 (16 comments)
(p.s. I put 2003 in the title above because it's the year of the article, although the book it's about was from 1956.)
https://books.google.com/ngrams/graph?content=Cybernetics%2C...