I enjoyed this book. Although personally I think it's a bit different than the other previous three books. The other three books have similarities in having a story plot that creating a really blur line between history and fiction. But in this fourth book, the history is like the inspiration of the fiction story, but I still liked it enough. I really enjoyed the thrill and excitement of Langdon adventure. And as a former international security student, I have an understanding regarding on security threats and this book is really interesting especially in that part. We all know about biological weapon and act of terrorism, but this book offers something that I haven't thought about before regarding on that issue. And it is so exciting. Overall, it is such an enjoyable read and very easy to digest. Thou it's not amazing, but still worth to read. :)