Don't miss the laugh-out-loud classic about a boy who leaps into battle when he's forced to share a room with his grandfather--now a major motion picture starring Robert De Niro, Uma Thurman, Christopher Walken, Jane Seymour, Rob Riggle, Cheech Marin, and Oakes Fegley! Peter is thrilled that Grandpa is coming to live with his family. That is, until Grandpa moves right into Peter’s room, forcing him upstairs.   Peter loves his grandpa but wants his room back. He has no choice but to declare war! With the help of his friends, Peter devises outrageous plans to make Grandpa surrender the room. But Grandpa is tougher than he looks. Rather than give in, Grandpa plans to get even.   They used to be such great pals. Has their war gone too far?   WINNER OF TEN STATE READING AWARDS AN IRA-CBC CHILDREN'S CHOICE "Peter tells this story with honesty and humor....By the story's end, Peter has learned much about the causes and effects of war--and human dignity."-School Library Journal "The humor of the story derives from Peter's first-person account and from the reader's recognition of Peter's valiant effort to maintain two mutually exclusive emotions."-The Horn Book Magazine