I, Libertine is a historical novel that began as a practical joke by late-night radio raconteur Jean Shepherd who aimed to lampoon the process of determining best-selling books.

He fabricated the author (Frederick R. Ewing) of this imaginary novel, concocted a title (I, Libertine), and outlined a basic plot for his listeners to use on bookstore clerks.

On September 13, 1956, Ballantine Books published I, Libertine simultaneously in hardcover and paperback editions with Shepherd pictured as Ewing, looking as dissolute as possible, on the back cover author's photograph.

An afterword states that "The story of Elizabeth Chudleigh is substantially true ...", which could easily be taken as being part of the hoax, ironically.

– can be seen on the paperback cover in a triangular area at extreme left, where it is part of the decoration on the coach door.