This book hooked me right from the start. I couldn't figure out if it was a post-apocalyptic novel or sci-fi and it's kind of both. I enjoyed the original premise and trying to figure out the mystery of the Library and Carolyn's plans. This book is good if you like lots of action and adrenaline. However, there were too many scenes of intense violence for my taste and at times I got a little sick of the repetitive dialogue and sarcastic repartee.