This listing is for Ian Caldwell & Dustin Thomason Rule of Four Books Different Covers Lot. 

The Rule of Four (2004) A novel by Ian Caldwell and Dustin Thomason

Tom Sullivan is about to graduate from Princeton. He's intelligent and popular, but haunted by the violent death several years earlier of his father, an academic who devoted his life to studying one of the rarest, most complex and most valuable books in the world. Since its publication in 1499, the Hypnerotomachia Poliphili has baffled scholars who have tried to understand its many mysteries. Coded in seven languages, the text is at once a passionate love story, an intricate mathematical labyrinth, and a tale of arcane brutality. Paul Harris, Tom's roommate, has deeply personal reasons of his own for wanting to unveil the secrets the book hides. When a long-lost diary surfaces, it seems the two friends have found the key to the labyrinth - but when a fellow researcher is murdered only hours later, they suddenly find themselves in great danger. And what they discover embedded in the text stuns them: the passion of a Renaissance prince, a hidden crypt, and a secret worth dying to protect.

All 4 paperback books are in excellent condition as shown in the photo.  Great book with multiple cover variations! Thanks for checking out all of our various treasures!  We have many similar items by similar artists, so make sure you search our store and combine purchases for additional discounts and savings on shipping!  We also have a ton of stuff not listed yet, so if you're looking for a specific title or additional artist items, please inquire as we may have it sitting here someplace or can easily find it for you!  Thanks again for the visit and good luck in your "Treasure" search!