The Rule of Four by Ian Caldwell & Dustin Thomason

At Princeton University, two brilliant students uncover a centuries-old mystery hidden within the pages of a Renaissance text known as the Hypnerotomachia Poliphili—a book so obscure it has confounded scholars for generations. As Tom and Paul race to decode its secrets, they find themselves entangled in a web of academic obsession, betrayal, and murder. What begins as an intellectual puzzle soon turns deadly, as the past and present collide in ways neither could imagine. Smart, elegant, and pulse-pounding, The Rule of Four combines historical intrigue with modern suspense—a gripping literary thriller about ambition, friendship, and the dangerous pursuit of truth.