Which is the most expensive novel of all time?

J.K. Rowling made seven handwritten copies of a children’s book called Tales of Beedle the Bard. They are handwritten, bound with brown leather, and decorated with moonstones. The author gave six of them to friends of hers but the seventh one was auctioned at a price of 3.6 million euros or about 4 million dollars. The book is a collection of stories told by the fictional character Beedle the Bard. The book is supposed to be a collection of stories about wizards and witches of the past to teach lessons to wizards at wizard schools such as Hogwarts. The stories contrast with “muggle” fairy tales in that it centers on the magic users themselves.

Also, the heroines tend to be much more active rather than waiting to be rescued by a knight in shining armor. The book is mentioned in-universe in Deathly Hollows as a book written for young wizarding students. In-universe, it was written sometime in the 15th century.