The 500 Hats of Bartholomew Cubbins is a children's book, written and illustrated by Theodor Geisel under the pen name Dr. Seuss and published by Vanguard Press in 1938. Unlike the majority of Geisel's books, it is written in prose rather than rhyming and metered verse. Geisel, who collected hats, got the idea for the story on a commuter train from New York to New England while he was sitting behind a businessman wearing a hat; the passenger was so stiff and formal that Geisel idly wondered what would happen if Geisel took his hat and threw it out the window. Geisel concluded that the man was so "stuffy" he would just grow a new one.