A boy (August) with rare medical conditions that deformed his face enters school for the first time during his fifth grade year. The book covers roughly the course of this school year, plus some flashback scenes. 
 Kids of those age are notorious for their capability for cruelty, though this book also explores the kinder, more compassionate side middle schoolers exhibit. 
 It's easy to read, predictable, and (perhaps over-obviously) pulls at your heart-strings with its sweetness and positive messages. Still, I liked it, and had fun reading it to my sons (14 and 12). Wonder alternates the narrator's voice among its chapters, and those can be especially fun to read aloud. 
 My younger son would give it 3.5 stars. I'm guessing he just isn't a fan of realistic-fiction, or maybe it reminded him too much of school and he's ready to be in the moment of his summer vacation. Either way, he said "it wasn't fantasy or sci-fi or action oriented enough." 
 It's probably the best for kids 9-12 that like this genre.