The Rule of Four by Ian Caldwell and Dustin Thomason is a runaway international bestseller, topping the charts on both sides of the Atlantic. But the foundation of The Rule of Four, as all its readers know, is a little-known text from the fifteenth century, the Hypnerotomachia Poliphili. Lurid, dreamlike, extremely erotic and written in many different languages and codes, the exact meaning of the Hypnerotomachia has eluded scholars for centuries. Now, in this indispensable, concise and thoroughly entertaining book, Professor Joscelyn Godwin, the translator of the first complete English edition of the Hypnerotomachia, guides the reader through its labyrinthine pages and unlocks the secrets and mysteries within Ian Caldwell and Dustin Thomason’s novel. He brings to life the worlds of both the Renaissance reader and the young Princeton undergraduate, setting both in the context of their time and place.