Jonathan Kellerman is a psychologist/author (or psycho author like myself) and I have enjoyed his Alex Delaware series. His character Alex is a child psychologist who consults on murder cases.
When the Bough Breaks is book #1 of a whopping 27 so far in the series. I stopped reading somewhere after #10 because the murder mystery thing was getting a bit gruesome for me, but I like how Mr. Kellerman weaves his psychological knowledge into stories.
In Chicago for the Romantic Times convention, I was talking to my brother-in-law about novelists who capitalize on their professional expertise. He's a fan of Michael Crichton and John Grisham, scientist and attorney, respectively. Wasn't it cool how Mr. Crichton used his knowledge about DNA to write Jurassic Park?
What professional expertise sparks your interest when reading novels?