However, there are many books based on his work:
* "Ripley's Believe It Or Not!" books: There are numerous volumes of "Ripley's Believe It Or Not!" books, both in print and digital format, featuring strange and amazing facts from around the world.
* Books about Robert Ripley: There are also biographies and historical accounts of Robert Ripley's life and work.
To be specific, you'd need to tell me what kind of book you're looking for.