From an exchange of letters in the New York Review of Books, on the limitations of current old-media-copyright-shackled efforts to digitize printed matter:

"[...] illustration and design are increasingly important in books for all ages. Unless and until some deal can be worked out for digital rights to images, the focus of the digital library is limited to text--just as we enter the golden age of visual narration. [...]"

and later, and not even concerning pictorial matter,

"[...] four eighteenth-century philosophers and statesmen Voltaire, Rousseau, Franklin, and Jefferson wrote so many letters to so many people that a digitized record of all their exchanges would make it possible to trace references through an enormous, transatlantic epistolary network and to show how the Republic of Letters actually functioned as a communication system.
http://3quarksdaily.blogs.com/photos/uncategorized/2008/05/27/books.gif

Unfortunately, however, [this particular, non-Google'ish digitization project's] publishers could not reach an agreement that would include all four correspondences, which come to nearly two hundred volumes in print. Therefore the digitization is now being restricted to the letters of European philosophers. [...]"
http://www.nybooks.com/articles/21630