7. Is it false respect, you may ask, to preserve intact and unblemished a beautifully printed book, an elegantly bound edition? Of course not. I'd no more scribble all over a first edition of "Paradise Lost" than I'd give my baby a set of crayons and an original Rembrandt! I wouldn't mark up a painting or a statue. Its soul, so to speak, is inseparable from its body. And the beauty of a rare edition or of a richly manufactured volume is like that of a painting or a statue.

8. But the soul of a book can be separated from its body. A book is more like the score of a piece of music than it is like a painting. No great musician confuses a symphony with the printed sheet of music. Arturo Toscanini revered Brahms, but Toscanini's score of the C-minor Symphony was so thoroughly marked up that no one but the maestro himself could read it. The reason why a great conductor makes notations on his musical scores—marks them up again and again each time he returns to study them—is the reason why you should mark your books. If your respect for magnificent binding or typography gets in the way, buy yourself a cheap edition and pay your respects to the author.

9. Why is marking up a book indispensable to reading? First, it keeps you awake. (And I don't mean merely conscious; I mean wide awake.) In the second place, reading, if it is active, is thinking, and thinking tends to express itself in words, spoken or written. That marked book is usually the thought-through book. Finally, writing helps you remember the thoughts you had, or the thoughts the author expressed.

10. If reading is to accomplish anything more than passing time, it must be active. You can't let your eyes glide across the lines of a book and come up with an understanding of what you have read. Now an ordinary piece of light fiction, like, say, Gone with the Wind, doesn't require the most active kind of reading. The books you read for pleasure can be read in a state of relaxation, and nothing is lost. But a great book, rich in ideas and beauty, a book that raises and tries to answer great fundamental questions, demands the most active reading of which you are capable. You don't absorb the ideas of John Dewey the way you absorb the songs of a popular singer. You have to reach for them. That you cannot do while you're asleep.

11. If, when you've finished reading a book, the pages are filled with your notes, you know you read actively. The most famous active reader of great books I know was President Hutchins, of the University of Chicago. He also had the hardest schedule of business activities of any man I know. He invariably read with a pencil, and sometimes, when he picked up a book and pencil in the evening, he found himself, instead of making intelligent notes, drawing what he called "caviar factories" on the margins. When that happened, he put the book down. He knew he was too tired to read, and was just wasting time.