Reading a book should be a conversation between you and the author. Presumably he knows more about the subject than you do; if not, you probably should not be bothering with his book. But understanding is a two-way operation; the learner has to question himself and question the teacher, once he understands what the teacher is saying. Marking a book is literally an expression of your differences or your agreements with the author. It is the highest respect you can pay him.

Friendship is a very taxing and arduous form of leisure activity.

There is no more irritating fellow than the man who tries to settle an argument about communism, or justice, or liberty, by quoting from Webster.

It's not how many books you get through, it's how many books get through you.

... always keep in mind that an article of faith is not something that the faithful assume. Faith, for those who have it, is the most certain form of knowledge, not a tentative opinion.

Men value things in three ways: as useful, as pleasant or sources of pleasure, and as excellent, or as intrinsically admirable or honorable.

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