Quotes from Mortimer Adler

If a book is easy and fits nicely into all your language conventions and thought forms, then you probably will not grow much from reading it. It may be entertaining, but not enlarging to your understanding. It's the hard books that count. Raking is easy, but all you get is leaves; digging is hard, but you might find diamonds.

The person who, at any stage of a conversation, disagrees, should at least hope to reach agreement in the end. He should be as much prepared to have his own mind changed as seek to change the mind of another ... No one who looks upon disagreement as an occasion for teaching another should forget that it is also an occasion for being taught.

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 question it, it answers you only to the extent that you do the work of thinking an analysis yourself.

The truly great books are the few books that are over everybody's head all of the time.