Diane deGroat is the illustrator of more than 120 children's books and the author-illustrator of other bestselling books about Gilbert, including Mother, You're the Best! (But Sister, You're a Pest!); Last One in Is a Rotten Egg!; Trick or Treat, Smell my Feet; Jingle Bells, Homework Smells; Happy Birthday to You, You Belong in a Zoo; No More Pencils, No More Books, No More Teacher's Dirty Looks!; Brand-new Pencils, Brand-new Books; and the New York Times bestseller roses are pink, your feet really stink. She lives in Amherst, Massachusetts.