Aside from that, it's a trainwreck. The writing sucks. The history is laughable. The vague theological musing about the sacred feminine read like a '70s New Age tract. Worst (?) of all, it's all just a rip-off of Holy Blood, Holy Grail
Geoff Pullum has a great post on Brown's stylistic atrocities. The opening sentence of the book ("Renowned curator Jacques Saunière staggered through the vaulted archway of the museum's Grand Gallery.") reads like a newspaper article, not an action novel. A bit later Brown has Saunière simultaneously freeze and turn his head. Then we have a silhouette staring! Silhouettes can't stare! Pullum has it exactly right: "Brown's writing is not just bad; it is staggeringly, clumsily, thoughtlessly, almost ingeniously bad."
All that before you even start thinking about the factual inaccuracies. As bad as Brown screws up French geography, it's to believe he's ever looked at a map of France, to say nothing of actually going there (as he's apparently done). Versailles is *not* northwest of Paris. There's absolutely no reason why someone arrested in France would be sent to prison in Andorra. The Priory of Sion a 20th-century hoax, not an ancient secret society.
Beyond the obvious factual errors, there's also a ton of things that just don't make sense. You're telling me that Robert Langdon, famous Harvard symbologist, doesn't know French? There's stuff like that throughout the book. Not necessarily "wrong," but endlessly grating. Dan Brown just doesn't know much about what the world is actually like. It's like he exists in some parallel universe where buildings exist in slightly different locations, dubious archives are completely trustworthy, and art historians don't know French.
Now you could very easily argue that that parallel universe is the world of fiction. Fine. But Brown makes a big to-do about how much research he does for his books, how everything is accurate. Hell, the first page of the book is entitled "FACT." And people seem to believe him. And that's the real problem. If everyone just took this crappy book as fiction, I'd have no complaints. Or at least I'd shut up about them. But when people buy into Brown's pseudohistorical tripe, there's a problem.
