Mr. Blue is a lovable cross-eyed cat. But he can't keep out of trouble. When the third-graders let him in the classroom-- he walks on the fresh paint, he eats the guppies in the aquarium, he bites Miss Pettit, the music teacher. You'd never think Mr. Blue would turn out to be a hero--but he does.
One of my favorite books from childhood-still have my Scholastic copy that cost 45 cents. Mr Blue is very dear to me as I had a Siamese cat growing up who "talked" to me and grabbed ankles in play.