Ylvisaker, Anne (2007). Little Klein. 186 pages. Grades 3-6.
Nine-year-old Harold Sylvester George Klein, known as "Little Klein," is the smallest and youngest in his family, and his brothers, "the Bigs," never let him forget it. One day, a dog named LeRoy finds Harold and follows him home. Soon the two are inseparable and they find themselves having one adventure after another. But, when disaster strikes and his brothers are the ones needing help, Harold takes action and saves the day.
This is a great story for kids who enjoy reading realistic stories about adventure and friendship between children and animals. Other books to try include: DiCamillo's Because of Winn Dixie, Naylor's Shiloh, and Twain's The Adventures of Tom Sawyer.