Ian Caldwell

Ian Caldwell, who studied history at Princeton, is best-known for his book The Rule of Four, which he co-authored with his friend and writing partner Dustin Thomason, whom he met in high school. Called "the ultimate puzzle book" by The New York Times, the erudite The Rule of Four is centered around four students attempting to solve a centuries-old mystery embedded in a Renaissance text. It spent 49 weeks on the New York Times bestseller list. Caldwell’s next book The Fifth Gospel was published in 2015.