Age: 8-12 years
Lexile: 640
Author: Smith, Robert Kimmel
Paperback: 160 pages
Publisher: Yearling Books (9/1/1984)
Product Dimensions: 5.2 x 0.4 x 7.6 inches

Peter is thrilled that Grandpa is coming to live with his family. That is, until Grandpa moves right into Peters 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?