To me, the definition of a good book is one that sucks you in to their world and that you can identify or sympathize with the characters. In my opinion, this is not a good book. Spoiler alert! There are so many holes in the premise that it's impossible to suspend disbelief. Earlier reviews mentioned a lack of the outside world, that it's like they're in a cocoon- that's exactly it. Forget all the questions of "couldn't more people have seen him disappear", "why didn't his time travel skills make headline news", etc.- because you'll be disappointed. The characters are detestable and selfish. And if you buy the whole premise of the book and do get sucked in to this world- it's incredibly sad if you think about it. The creative writing was the only redeeming quality.