Changes, by Jim Butcher

I've been looking forward to the latest in the Dresden Files series for quite a while, and it doesn't disappoint. Butcher doesn't mess around setting the scene; on the first page his ex-girlfriend Susan shows up to tell him that the Red Court vampires have kidnapped their daughter. Since Harry had no idea that he and Susan had a child, you can imagine what a shock this is. Before it's quite worn off, Susan and her sidekick, Martin, of the anti-vampire Fellowship, and Harry are off to burglarize the offices of the local branch of the Red Court, seeking information. The bad guys blow up the entire building to keep them from succeeding, and we're off and running with the action.
Harry attempts to enlist the help of the White Council, but they're unwilling to get involved in confronting the vampires, as the vamps have recently sent an envoy to propose a peace treaty. Supporting Harry in his quest might disrupt that fragile process. Of course, Harry has other allies, such as his apprentice, Molly, policewoman Karen Murphy, Soldier of the Cross Sanya, Father Forthill, and a few connections in the land of Faerie, so he begins to gather them to help rescue his child.
He's pursued by assassins from the Red Court, and faces nightmarish creatures summoned out of Mayan legend as he tries to find out where the vampires have taken his daughter. What starts out appearing to be simple revenge against Harry for killing one of their nobles rapidly begins to take on more global application. Harry is forced to make some choices he's long avoided, and bargain with beings far too powerful to cheat, in order to succeed.
Well-plotted, lots of action, a good ride throughout. My only gripe is that Butcher leaves us with a cliff-hanger ending, and I'm not sure what he intends to do with Harry next.