The 500 Hats of Bartholomew Cubbins

A boy named Bartholomew Cubbins must remove his hat for the passing king, but a new one keeps appearing, escalating into a comical and tense situation with the king's guards. Written in prose, unlike most of Dr. Seuss' books.

Dr. Seuss, who was a collector of hats, got the idea for the story when he was on a commuter train from New York to New Engand, while sitting behind a businessman wearing a hat. The businessman was so stiff and formal that Geisel idly wondered what would happen if he took the man's hat and threw it out the window, and he artistically concluded that the man would "simply grow a new one".