And just so we're clear, what they mean by "technical" is "software person". Are you a linguist? MD? Sound engineer? That's not "technical" in O'Reilly's book.
Chemist? Number theorist? Lawyer? Botantist? Cartographer?
Criminal Psychologist? Statistician? "Non-technical".
I say anyone involved in making software is a developer.
(This isn't even counting the overlap when one of those mentioned can _also_ program, even if it might or might not be one of their official tasks.)