Dead tree libraries will eventually become obsolete as books are converted to digital format.
You're still missing the point. I'm talking about the difference between a thing and an idea (which might be represented by a thing). I wholeheartedly agree that the "dead tree" libraries will become more and more obsolete as we turn more toward digital versions (much to the delight of Al Gore and the rest of the tree huggers).
The thing that I'm calling a book will be the same thing whether it be written by hand on parchment, printed by a Gutenberg printing press, bought online at Amazon.com, checked out of a library, listened to on a CD, or read online. It is that idea which is expressed that I am calling a "book".