 Donald Pease notes that The Cat in the Hat shares some structural similarities with other Dr. Seuss books . Like earlier books , The Cat in the Hat starts with " a child 's feeling of discontent with his mundane circumstances " which is soon enhanced by make believe . The book starts in a factual , realistic world , which crosses over into the world of make believe with the loud bump that heralds the arrival of the Cat . However , this is the first Dr. Seuss book in which the fantasy characters , i.e. the Cat and his companions , are not products of the children 's imagination . It also differs from previous books in that Sally and her brother actively participate in the fantasy world ; they also have a changed opinion of the Cat and his world by the story 's end . 
