14. A Treatise of Fruit Trees – $4.6 million (1700s)
Written in the 18th century, the Treatise of Fruit Trees is, well, a book on fruit trees! While its topic may not be as exciting or gripping as the themes of the other books on this list, it does contain some stunning color illustrations and paintings of 16 different varieties of fruit trees and their details.
So when this book was auctioned in Brussels in 2006, it ended up raking a total of $4.5 million!