A book is like nature or the world

Here's a good quote to follow up the annual reading list post:

"If you ask a living teacher a question, he will probably answer you.  If you are puzzled by what he says, you can save yourself the trouble of thinking by asking him what he means.  If, however, you ask a book a question, you must answer it yourself.  In this respect a book is like nature or the world.  When you queston it, it answers you only to the extent that you do the work of thinking and analysis yourself."

--Mortimer J. Adler and Charles Van Doren, How to Read a Book (Touchstone, 1972):  p. 15.