If you haven't heared about it yet: The Faddan More Psalter is a book from appr. the 9th or 10th century found in an Irish bog in 2006.
It was bound as a libri sine asseribus, a book with a flexible leather or velum cover instead of wooden boards. In german this is called Kopert (from lat. coopertium), a type of binding I'm exspecially interested in. Nothing fancy, this was somehow the medieval version of a paperback...
You can read more on wikipedia: Faddan More Psalter
By the way, the german version of this article was a birthday present from a very dear friend last year :-)