This novel is the second in a series (the first was published last year). The story is about a family of treasure-hunters, and the narrator/protagonist is the youngest son. It's got something of an Indiana Jones feel to it, family-style, with gangs of bad guys and a multi-talented team of good guys.
The humor is evident from Chapter 1, where the protagonist accepts a dare to jump his skateboard over the principal's hot rod. (Spoiler: it doesn't end well.) The author is really quite a master of dialogue, and so the exchanges between characters are often hilarious. He adds just enough detail about facial expression, hand motions, and that sort of thing to help us feel and see the humor. Conversations are funny; situations are funny; the kid-logic is funny; even the villains are funny in their ineptitude.
The author of this novel had a great deal of fun writing his story, and he managed to enjoy himself somewhat through the initial editing process. When I asked him to go back one more time and fix some punctuation problems and gaps in the plot, his humor momentarily left him. He might be burned out from the revision process, but the book he has written is a great success!