John Killian

The quotation is everywhere, but who was/is Gentleman John Killian?

It's from John Kilian Houston Brunner's (note: only one l in Kilian) classic SF novel Stand on Zanzibar. The original source is a chapter heading from that book, It's Supposed to Be Automatic But Actually You Have To Press This Button.

A fictionalized version of JohnBrunner appeared in at least one of Spider Robinson's Callahan's Bar stories, under the name Gentleman John Kilian. The variant quotation may derive from one of those, or possibly it's just undergone the folk process.

http://en.wikipedia.org/wiki/John_Brunner_%28novelist%29

http://www.nesfa.org/Recursion/recursive_R.htm (scroll down to the Spider Robinson section).