This book takes a long time to get going. I mean a LONG time. It wasn't until chapter 13 that I thought to myself, "oh yeah, this is good!" The beginning is convoluted, giving you a feeling that you've jumped into the middle of things. We know Incarceron is a prison, we know things are odd in the real word but we have no clear idea why. I was desperate for a little back story, not only to clarify things but to give me a reason to be invested. When it finally does come, the back story is still not as fleshed out as I'd like, but it does help the story to be more concrete.
The characters are interesting and the premise intriguing (once you get past the first twelve chapters). The ending however, is somewhat unsatisfying because so many loose ends are left. Clearly, the author intended to make this a series and so I'm okay with that. I just hope she clears up the big "is he or isn't he" mystery in a way that I can live with.
I will definitely read the sequel, Sapphique.