Although I admit that the book finally 'picks up' some momentum after the initial 200 page slog, it never really becomes a compelling read. I did, in fact, finish this book, but only because it's difficult for me to abandon any book I've started. There is absolutely no basis for comparison between "The Rule of Four" and any Dan Brown work beyond the tenuous thread that some historical puzzles are being solved within the pages. The fact that the plot line of "The Rule of Four" is anchored in an actual historical text does nothing to lift it from its plodding pace. My copy will be donated.