Unfortunately after reading Brown's 5th book, I still stand by "Angels & Demon's" and "The Da Vinci Code" being my two favorite Robert Langdon books. The book seemed to both drag in parts and yet have a plot that went by fast...I don't know how. A couple of the twists I figured out early on and the climax was a bit of a let down. Also, I initially liked this series because of it's focus on puzzles and symbology since that is Langdon's profession. This book didn't really have a lot of that and what it did seemed forced. A bit of a letdown.