Fiction by R.J. Palacio.
I think this book is intended for kids, since the hero is a ten-year-old, but I'd say it's really for teens to adults, because it really deals with a troubling set of emotions. But maybe kids can understand it on their own level.
The boy in the story (August) has a facial disfigurement, and his parents decide to send him to school for the first time starting in fifth grade, which is Middle School. Obviously, this is a difficult transition.
I really liked this book because it did not go for the formulaic ideas one might expect from this kind of story:
Handicapped Boy =Saint
His family= Perfect and Ever Loving
His friends = Loyal and True
His enemies = Bad Bad Kids
The Ending = Everyone Happy Happy + Bad Kids Punished
This is a good story about realistic people. I haven't seen the movie, but this book is definitely worth reading.