I can think of no better way to describe this series (The Spellman Files, followed by Curse of the Spellmans) than the way one reviewer has already put it: Harriet the Spy for grown-ups.
Or at least thirty-somethings who aren't quite ready to be grown-ups.
Or who want to be grown-ups on their own terms, which in this case includes case reports with lots of footnotes and not so much a room full of playpen balls.
Anyhow, it's hi-larious and highly recommended. I'm already anticipating the next one, which — given the tendency for the titles to sound like installments in a horror movie series — would have to be Bride of the Spellmans. And after that, Son of the Spellmans. And then The Spellmans Meet the Wolfman.