I am sort of torn with this book. On one hand it was a real page turner and held my interest. On the other hand, there were a lot of parts in the book I found not really believable. For example in the space program they really do look into things like personality profiles and such insuring that the most stable folks possible will be selected, and that astronauts will work well in a group together. This didn't seem to happen and to be blunt I find it hard to believe in the future that it would not still be the case, even more so for an extended mission to Mars. Also, the story had a lot of other less believable events that kind of stretched my suspension of disbelief. As I said, I am torn. For light reading, I found it enjoyable up until the end. The mystery kept me reading, but the resolution of the mystery left me just not totally buying the resolution. I want to go on and point out a lot of what I am talking about piece by piece, but I also don't want to spoil the book for anyone that might want to pick it up. I must say, I don't regret purchasing it. I was a bit disappointed in it, it just seemed to hold a lot more promise.