1. You know you have to read "between the lines" to get the most out of anything. I want to persuade you to do something equally important in the course of your reading. I want to persuade you to "write between the lines." Unless you do, you are not likely to do the most efficient kind of reading.
2. I contend, quite bluntly, that marking up a book is not an act of mutilation but love.
3. You shouldn't mark up a book which isn't yours. Librarians (or your friends) who lend you books expect you to keep them clean, and you should. If you decide that I am right about the usefulness of marking books, you will have to buy them. Most of the world's great books are available today, in reprint editions, for a modest sum.
4. There are two ways in which you can own a book. The first is the property right you establish by paying for it, just as you pay for clothes, and furniture. But this act of purchase is only the prelude to possession. Full ownership comes only when you have made it a part of yourself, and the best way to make yourself a part of it is by writing in it. An illustration may make the point clear. You buy a beefsteak and transfer it from the butcher's icebox to your own. But you do not own the beefsteak in the most important sense until you consume it and get it into your bloodstream. I am arguing that books, too, must be absorbed in your bloodstream to do you any good.
5. Confusion about what it means to own a book leads people to a false reverence for paper, binding, and type—a respect for the physical thing—the craft of the printer rather than the genius of the author. They forget that it is possible for a man to acquire that idea, to possess the beauty, which a great book contains, without staking his claim by pasting his bookplate inside the cover. Having a fine library doesn't prove that its owner has a mind enriched by books; it proves nothing more than that he, his father, or his wife, was rich enough to buy them.
6. There are three kinds of book owners. The first has all the standard sets and best-sellers—unread, untouched. (This deluded individual owns woodpulp and ink, not books.) The second has a great many books—a few of them read through, most Of them dipped into, but all of them as clean and shiny as the day they were bought. (This person would probably like to make books his own, but is restrained by a false respect for their physical appearance.) The third has a few books or many every one of them dogeared and dilapidated, shaken and loosened by continual use, marked and scribbled in from front to back. (This man owns books.)
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 14h'th 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 Dewey3 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.