Dead Witch Walking by Kim Harrison
Robert read the omnibus version called This Witch for Hire. It contains Dead Witch Walking and The Good, The Bad, and the Undead.
A guilty pleasure of mine, pardon the pun, was reading the ANITA BLAKE series by author Laurell K. Hamilton. Unfortunately, like many readers, I was turned off by the direction that the series was heading with later novels, and eventually stopped reading the books altogether with 2003’s Cerulean Sins.