I write books for a living. Mostly fiction:

http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dap...

Which is not to say that I haven't written technical books, back in the day:

http://www.amazon.com/Web-Architects-Handbook-Charles-Stross...

I'm not self-published -- I've got Ace (aka part of Penguin USA), Orbit (aka Hachette) and Tor (aka Holtzbrinck) as my publishers.

Yes, I do this for a day job.