He Tried Writing for Adults, Too
In 1939, “ The Seven Lady Godivas: The True Facts Concerning History’s Barest Family ” was published, which featured semi-nude drawings of women. It wasn’t very successful, which Seuss attributed to his inability to draw the ladies “sexy” enough.

Source: Abe Books
Seuss tried the adult audience again much later in 1986 with the book “ You’re Only Old Once ,” which joked around about all the things that happen as we reach old age. I got a get a hold of that one!