I was disappointed about this book. I like Eco, but I just kept waiting for the book to get better, when in fact, I was just disappointed at the end.
What I didn't like about it is that it is a very passive sort of book. The protagonist just sits there telling a story. A story that is worth telling, but just barely. There is tons and tons of stuff to read through that is relatively meaningless. Some pretty odd stuff. Thought provoking at times perhaps if you like that sort of stuff, but I was not overly interested in most of it.
What made this book a disappointment is that after the first boring 400 pages, nothing really happens. The protagonist just says "I stood there and watched" and narrates to the end. No suspense. Things just happen and turn bad and no effort is ever made to change anything. You never sit there and think "I wonder if they manage to get out of this". They just don't and you know if from the beginning of the end...
This book is the opposite of the Da Vinci Code. Similar topic, but it's all fake and moves extremely slowly. The book never even pretends to tell put the protagonists into something real. All they do is make up a story, which - for a little while - appears to be real, but isn't.
In hindsight, I regret having spent the time to read through this. I am sure there is lots of good wisdom in this book if you read it for more than just pure entertainment, but the book never got me interested enough to figure out what it was.
Some fellow reviewers say it was hard for them to understand the book. I think that may be true if you are not familiar with the subject matter. If you have read books like Holy Blood, Holy Grail, or are even vaguely familiar with Templar or mason books, you will only find a few short passages that spark your interest. Perhaps when Eco wrote this book, some of these passages were more interesting. Possibly also because some of what he writes about the use of a text processing computer may have been more believable then...