In 1960, editors at Random House told The New Yorker that the demographic for the works of Theodor Geisel, a.k.a. Dr. Seuss, was children aged 5 to 9 years old. Books like How the Grinch Stole Christmas and The Cat in the Hat have become perennial sellers, with the writer-illustrator as closely identified with childhood entertainment as Mister Rogers.

But Dr. Seuss had a mischievous side, one that was in sharp contrast to the kid-friendly material that kept him at the top of the bestseller lists for decades. Largely unseen by the public, it was directed at his editorial supervisors at Random House. When Geisel submitted the manuscript for Dr. Seuss’s ABC, an alphabet primer published in 1963, editor Michael Firth was surprised to see the letter “X” accompanied by a naked woman with the following copy:

“Big X, little x. X, X, X. / Someday, kiddies, you will learn about SEX.”

Geisel knew the page would never see the light of day: His habit of including lurid material stemmed from wanting to make sure his editors were paying attention to his work. (He may also have been trying to avoid the monotony that comes with all-ages prose.) Speaking of his work process, Geisel once said that his first drafts were full of “swear words and dirty words and everything else … then I go back and clean it up, have a little fun with it.”

Random House

Whether there was ever an X-rated draft of Green Eggs and Ham has apparently been lost to history. The only mature-audience title Geisel published was 1939's The Seven Lady Godivas, which was created with an ambition to “draw the sexiest women I could.” (The nudist Godivas appear naked throughout the book.) It sold poorly, however, moving just 2500 copies during its initial release. For Seuss fans, it was better for both the author and his brand that he keep his more salacious urges to himself.