Earlier quoted context omitted.
> Read books are far less valuable than unread ones. izzit me or is that total garbage? The only information of value is that which you can use, if it's in a book you've never read it's effectively nonexistent. I get text books to stuff them into my cranium, not have them sit around as handy doorstops. Might as well leave them in the bookshop until you need them. They're just as unread and you have cash in your pocke…
The information is more useful once read, but once you know it you don't need the book any more
Unless you anticipate wanting to check and re-check the contents. On a shelf right beside me (as opposed to the plethora of shelves in the room we call "The Library") is a copy of "Concrete Mathematics" by Graham/Knuth/Patashnik, because I am occasionally going through it again. Quite happy I have not decided to let it go.