The story is fairly simple. Three editors, very smart bordering on genius, read esoteric material for their publisher. They read books by people they have dubbed “Diabolicals”. These diabolicals write about secret societies over the ages. Templars, Illuminati, Rosicruscians, Masons, Neo Templars, Jesuits, everyone features in these books. There are mystical ceremonies, initiation rites, many unbalanced, bordering on crazy, characters. In the midst of all these magical, mystical things Belbo, Diotallevi and Casaubon are the only sane voices. And then they decide to have some fun with all the vast information they have gathered on all these cults over the years. And we all know how that usually turns out, just harmless fun.
For me the redeeming feature of this book was its climax. The entire story is told in flashback right before the climactic moment. The book is a tough read unless the reader has in depth knowledge of history, religion, and the cultic societies. I say tough because it isn’t that the storyline is hard to follow without this knowledge, you always know where the story is headed and it has an extremely elegant climax. But reading this book without having at least some background in mathematics, history, religion, templars etc is like walking down a path with a scenic view, in the fog. You can grope your way home but the beautiful vistas are forever lost to you.