The questions remains, probably, what it means for a book to be 'read'. I'd posit that that books are only valuable in your possession if you know it - this spe

The questions remains, probably, what it means for a book to be 'read'. I'd posit that that books are only valuable in your possession if you know it - this specific book - exists, maybe even where exactly in your house if you have a lot, and you have a basic idea of the contents. So you have to open them at least once and get a general overview of the index, maybe the illustrations, maybe even a bit more. Is this book still unread? I'd say truly unread books are worthless without a search function, which is not yet well implemented in the physical world.