The first "Out of Time" book (Yanked! by Nancy Kress) has received unjustified criticism on Amazon. I’ve attempted to provide rebuttal, but for some reason my reviews have not been published (I’m still looking into this). Since it’s unlikely that Amazon would publish my detailed rebuttal anyway, I provide it here.
Contrary to what the Amazon reviewer states "Yanked" does not show the heroes resorting to savagery to win out over the aliens, nor does cock-fighting play a role in the heroes’ plans. Although one of the Yanks is a violent, savage fellow, he is also a realistically described child from his time period (19th century England), and more importantly, his use of violence never helps the team win out over the aliens. Quite the reverse: Robby threatens several people with his knife (including a 7-year old girl), leading to unnecessary tensions between allies, and then kidnaps a baby to turn her over to aliens. He also stabs the team leader. Each of these actions is very much to the team's detriment. Robby’s affection for cockfighting disgusts his teammates and does the team no good. Robby becomes a help to his team only when he forgoes violence against people and animals, and follows the plan his teammates have arrived at.
The reviewer is also mistaken in the belief that violence is endorsed when the teen from the future reacts to Robby’s "sale" of a baby to the aliens by beating Robby up. The teen from the future is highly regarded by the entire team well before this point (his knowledge and helpfulness are clearly useful). Furthermore, it is clear that he considered his violent outburst as a horrible thing - he regretted it immediately and probably suffered more from remorse than Robby suffered from his wounds; his violent outburst was at any rate in no way like a gang initiation ritual.
The use of trickery is another story. All the Yanks use trickery to win out over the aliens and so what! A good class discussion could occur concerning when trickery is appropriate, but most people would agree that while to trick a widow out of her pension is bad, to trick a thief into returning his loot is not - and the situation in Yanked! is much closer to the latter than the former. Furthermore, a distinction can be made about what impulses are being taken advantage of by the trickery. I tend to believe that even when the cause is just, one should avoid trickery that takes advantage of someone's good impulses (sympathy, etc) - this is why con artists who run fake charities are generally considered to be worse than those who run "something for nothing" scams. In Yanked! the successful trickery takes advantage of the opponent's greed and cowardice. I see no problem with the morals involved in that.
As to whether the book will appeal to real-life teenagers, I can only say that where the book has been taught, it has inspired teenage students to think and to act. Any book that can inspire that kind of learning is clearly successful in the only way that counts.