Palimpsests and hidden manuscripts

A palimpsest is a manuscript page, either from a scroll or a book, from which the text has been scraped or washed off so that the page can be reused for another document. As well as for this purpose, old manuscripts were often used for bookbindings and in the binding structure. So today conservators are sometimes lucky to find old manuscripts when investigating old books.

An example of a binding (Northwestern University/ Art Institute Chicago):
Article with pictures attached: Imaging Reveals Medieval Manuscript Hidden in Book Binding. To make the writing visible they used x-rays. (Link)
Another article on this matter with an attached Video: Fused Imaging Reveals Sixth-Century Writing Hidden Inside Bookbinding.