"The Rule of Four is a thrilling mystery novel that takes readers on a journey through intricate labyrinths of love, math, and brutality. Ideal for lovers of historical puzzles and suspenseful thrillers alike, readers will be kept on the edge of their seats until the last page."

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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: a narrative detailing the passion of a Renaissance prince, a hidden crypt, and a secret worth dying to protect ...

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