I usually steer clear of books on the bestseller lists for a reason. Nearly always, they become popular because they speak to the least common denominator in readers (and, of course, because the publishers spend bundles of money promoting them). With this book, however, I'd seen a couple of positive reviews in book blogs (e.g., Jessamyn ), and I usually enjoy literary thrillers, so I gave it a shot.

The Rule of Four is clearly being marketed to the people who have kept The Da Vinci Code at the top of the bestseller list for well over a year. There are some similarities between the novels: long-hidden secrets, mysterious Renaissance figures, and — lest I forget — awkward writing. Caldwell and Thomason try much harder than Dan Brown to create characters with depth, and they succeed in creating colorful backgrounds for the protagonists. Unfortunately, there's a lot of detail that is only ornamental, and they don't come close to Brown in the area where he excels: page-to-page suspense. The Rule of Four isn't bad, but it's also not great. If you want to read a well-written literary mystery, try Allen Kurzweil's The Grand Complication.