George Ellis makes an interesting point about the abstract nature of information contained in books. This seems to be very much the same idea as what Karl Popper called the 'World 3' of objective knowledge, which he loosely categorised as 'the contents of books and libraries'. This has been one of the less-regarded parts of Popper's thought, sometimes decried as 'mystification'. It is good to see these ideas being supported.

David Bawden, London