From the author of the Silverwing trilogy and Airborne, Half Brother is a compelling and thought provoking book. When 13-year old Ben leaves his old home, friends, and school behind to work on an experiment that his father, a behavioral scientist, is researching, he is apprehensive at first. His father is interested in whether a chimpanzee can learn language. To find out he adopts a baby chimpanzee, and tells Ben to treat it like a little brother. While dealing with a new school, new home, new girlfriend, and adolescence, Ben must also deal with a mischievous chimpanzee, Zan. As the project progresses, Ben begins to see Zan as a real little brother. Then, when everything that Ben cares about is put into jeopardy, it all becomes a question of how far they are willing to take the experiment. This well told, tear-jerking book challenges the thin line between human and animal. It a great book for the teenage animal lover crowd.