Like (Printz award-winner) Midwinterblood, this title has several sections spanning different places and times, but tied together by a concept. In this case it's the spiral, and it's complicated. I didn't always enjoy reading this book; it made my brain hurt sometimes. But it haunted me when I wasn't reading it, and I'm still a little unsettled by it. So I think that means it's kind of masterful.