I adore Daniel Kraus and all his weird, deeply psychologically troubled characters and plots. 
 This was not one of them. 
 Oh, it was good, and enjoyable, don't get me wrong. But it wasn't what I'd expected it to be. It's a troll-hunting adventure story, giant trolls poised to take over the city and a boy discovering his legacy as a troll-hunter, and coping with his dad's neuroses and paranoia. It's gross and gory in places, in the ways that will appeal to 8th-grade boys like crazy. 
 But that's just it--this is at the upper end of middle-grade or the lower end of teen. The characters are high school sophomores, and in the beginning they read a little older and in the middle a little younger. 
 And of course it's the beginning of a series. Of course it is.