I very much enjoyed this book for being a book about a book. I liked the framing device of a book conservator discovering details and clues in a manuscript, and then jumping to the 'actual' story of "what happened." However, I found the 'modern' details to be a peculiar mix of overwrought and dull... the conflicted relationship with the mother, the unlikely romance, the dying child... I could have done without all of that. The book also suffered from "oh-no-is-my-book-boring?-syndrome" - where I feel that the author, after having got most of the way through writing a quiet yet interesting story, suddenly decides there isn't enough action in it - and right at the end there's a heist! Crime! Murder! Drama! (not to mention a likely exaggeration of security systems... though that might not be such a bad thing...)
That said, I did really like the writing style, and I found the stories of the various people through whose hands the book passed to be compelling.