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. I insist, quite bluntly, that marking up a book is not an act of damage but of love.
There are two ways in which one 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 buying is only the first step to possession. Full ownership comes only when you have made it a part of yourself, and the best way is by writing in it. A comparison may make the point clear. You buy a piece of beef and transfer it from the butcher's icebox to your own. But you do not own the beef in the most important sense until you eat it and get it into your blood. I am arguing that books, too, must be absorbed in your blood to do you any good.
There are three kinds of book owners. The first has all the standard sets and bestsellers—unread, untouched. 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. The third has a few books or many—every one of them worn, shaken and loosened by continual use, marked and scribbled (涂写) in from front to back.
Why is marking up a book necessary to reading it? First, it keeps you awake. (And I don't mean only 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. The marked book is usually the thought-through book. Finally, writing helps you remember the thoughts you had, or the thoughts the author expressed.
