“The Rule of Four” is a novel written by Ian Caldwell and Dustin Thomason that revolves around cracking the code in the 500 year old obscure book “Hypnerotomachia Poliphili”.

That book is written in a mixture of many languages by an unknown author and is rather weird and dense. Strangely, the acrostic formed by the first letters of each chapter reads “Brother Francesco Colonna Dearly Loved Polia” in Latin. This is what sets off the protagonist and his friend Paul on a mission to crack the code and make the book reveal its secret.

I liked the book a lot and found it engaging though not gripping per se. Comparisons with “The Da Vinci Code” are inevitable, but I would say that this book is neither as fast-paced nor as heady with an overdose of information as that one. Moreover, the narrative is not linear and goes back and forth in time, which initially disoriented me a bit. That does not mean however, that this book is any less enjoyable. This book actually bothers to flesh out the characters and their relationships with each other.