Ian Caldwell & Dustin Thomason, The Rule of Four, 2004.
yadda yadda two Princeton students trying to solve riddles yadda yadda in the middle of a poorly written murder mystery yadda.
This book was poor. It was poorly written, poorly plotted, and poorly conceived. The only thing to recommend this book at all--and what made me downright eager to pick it up--is that it's structured around the Hypnerotomachia Poliphili. The HP is an endlessly fascinating book, and The Rule of Four persuaded me to get my copy down from my shelves, and peruse it again.
Read the HP. Forget about The Rule of Four and its endless and trivial obsession with steganography. If you really want something fun to think about, the Hypnerotomachia Poliphili is the way to go. You can see the original--in its wacky combination of languages--here. You can buy an English translation, like me, here.