I had some trouble with this book--mostly because I have issues with dark creepy tunnels and things that go bump in the night. Like Freaks. *shudder* (So I had anxieties with the first one hundred-or-so pages that took place underground. Issues like sleeping badly and jerking awake every couple of hours. Because Freaks. And dark tunnels. Effective writing, that.) 
 That said, it was a fascinating, well written, gripping story. I'm glad I have the rest of the trilogy waiting.