This book sat on my shelf being judged for it's cover and the short synopsis on it for far too long while I wondered what drew me to it in the first place. But when I finally gave it it's chance I regretted taking so long almost immediately.
The book sweeps you away pretty quickly, bringing up questions and hypotheses in just the first few chapters that dont pay off until the final pages (I was worried too much was going on so far in, and learning it was a series that it would all be pushed along, but the author rewards you, don't worry). I also have a talent for predicting twists and was sure I had this right away, I didn't and love the book all the more for it. 
The humor was well spread out and felt more as a natural evolution and enhancement to the story than something forced upon the reader. It's a book that can be funny, not an every page has to have a dozen punchlines funny book, which while are fun in their own right, are not generally my cup of tea (I love you anyway Adams and Pratchett).
I highly recommend The Rook for anyone who wants some mystery, some spy craft, intense (and unique) fight scenes, and equally unique super powers.