The Hexologists is a Lot Of Fun. It's a solid urban fantasy with a good mystery—a claimant to the throne, blackmail, a king who's suddenly trying to set himself on fire. It's a wonderful steampunk world with multiple forms of magic, including but not limited to artistic hexes, industrial alchemy, and a carpetbag full of magical artifacts. It's funny. The characters are great across the board, but the protagonists are especially good—morose and cynical Isolde, cheery and trusting Warren. There is a dragon, a sea monster, and creatures from hell dimensions. There are some good twists and turns and I didn't see the ending coming until it was almost on me (read: 1-2 pages early).
In short, it's got a little bit of everything that makes a story like this satisfying, and if you're looking for a smart-fun fantasy read this fall, you should definitely check it out. There are presumably going to be sequels and I'll be watching for them.