Couldn't finish it!
I loved Da Vinci Code and other earlier works, but this one drove me crazy. It gets bogged down when he describes the city of Florence in such painstaking detail that you actually forget what had been happening before he explained the history of Boboli Gardens! I use that example because it is as far as I got. Whenever Langdon is present it slows down for this exposition. Other parts without him move at a much more reasonable pace for an "action" novel. Too bad, because I was really looking forward to it. Fortunately it was a library book and not a purchase!