5 Reasons to Write in Your Books
Scandalized by Writing in Books? C.S. Lewis Did It. So Did U.S. President John Adams. So Should You
When I die, my kids—or some lucky sap at an estate sale—will end up with my library. As they riffle through the pages, they’ll probably note the embarrassing number of coffee stains and all my marginalia.
Some of you will be scandalized: writing in books! Yes, and I can’t help it. I’m an inveterate scribbler. That’s especially true when it comes to nonfiction, but even novels suffer a few asterisks, underlines, and comments when deserved. If writing in books ever becomes illegal, you’ll find me in the prison library, lurking in a corner, sharpening a smuggled pencil.

Lest you think of my determination as unwarranted, here are five reasons I recommend the practice.
1. Compensating for Memory Loss
Besides his controversial politics, theologian Rousas Rushdoony was famous for reading a book most every day. What’s more, he also underlined key passages with a ruler and indexed important ideas in the back of the book. Rushdoony was in many ways extreme, but this practice seems one eccentricity worth emulating.
Montaigne disclaimed any facility of memory and said he couldn’t recall what he had read. To compensate he routinely scribbled marginalia in his books and even brief summaries of what he found useful. “I have adopted the habit for some time now of adding at the end of each book . . . the time I finished reading it and the judgment I have derived of it as a whole,” he said.
No one can remember everything they read. Underlining, jotting, circling, asterisking, annotating, indexing (even just a few points or topics) can help you later access a book and its information when memory inevitably fades. They’re like trail markers still visible through an overgrown path.
This is especially vital when it comes to research. I’ve written several books, and I’m I’m wrapping up another. If I didn’t write in my research materials, I’d be lost.
When I was working on my Paul Revere book, I remember hesitating over Charles Ferris Gettemy’s biography, The True Story of Paul Revere. The book was over a hundred years old. I can’t write in it, can I? It felt like some sort of aesthetic crime. But then, no. I need to keep track of ideas and details. Why did I have it to begin with? To use. Once I ditched my reservations, the payoff was immeasurable.
2. Retracing Your Intellectual Journey
Related to memory, writing in your books helps you access the state of mind you were in when you experienced a particular text. We all read in contexts. We have certain arguments going on at one time and not others; we have issues we’re grappling with unique to those times and places.
Ideas and emotions run in streams peculiar to the moment. And once the moment passes—and how they influenced your reading and thinking—they’re gone. All those scribbles and scratches serve as a means for documenting that singular context. The more thorough your note-taking, the more beneficial later on.
The risk here is that you may go back and find yourself embarrassed by your earlier observations. You might see how you were going down a bogus track when you last read Such and Such by So and So. You might cringe at an opinion you once held. Happens to me all the time. (Despite the fact I regularly cull my library, I actually keep a particular book on my shelves just to remind me of this dynamic; if you pick up my library at that estate sale you can guess which one.)
That said, if you take up the practice yourself, you may also find truly valuable insights about your own personal development you might otherwise have lost. In fact, I bet you will.
3. Conversing with the Author
Writing in your books is like talking with the author. It’s not always the best way, of course. But when the author’s dead, it’s the best you’re going to get. That’s probably true if they’re alive as well. And speaking as a former publishing executive, you might be grateful for the distance.
Books are written to start conversations. Reading itself is part of the reader’s role in the dialogue, but responding in the margins is as well. Those affirmations, qualifications, and objections go down on the page as part of an exchange.
American Founder John Adams offers an example. He was “the greatest marginalist” among his peers, according to historian Richard Brookhiser:
He wrote comments in fewer than 10 percent of his books, but when he got going—usually in works of history or political theory—he sometimes added thousands of words of his own to the text.
Adams’s notes are full of reactions, rejoinders, and counterclaims. He treats the margins of the page as his place in the conversation to toss in a dismissive laugh (“ha! ha! ha!”), short objection (“Not always”), or lengthy rebuttal.
For what it’s worth, Stalin provides another example. “He scrawled critical comments and abuse across pages with the same blue crayons he used to sign death warrants and initial treaties,” writes Nigel Jones, reviewing a recent book on the dictator’s reading habits.
What about the authors themselves, would they be offended? I once received an email from Charles Ferris Gettemy’s great granddaughter. She’d read that I’d written in my copy of his book. While she said she’d never write in her own copy, she wanted to assure me that her great grandfather wouldn’t have minded.
I’ve not asked many writers about this, but here’s my basic assumption: They’re thrilled beyond measure to learn someone took their work seriously enough to mark it up. And if it helps you more thoroughly engage with the ideas or use them later, whip out your pencil and go to town.
4. Facilitating Self-Discovery
Reason 4 plays off of Reasons 2 and 3 above, but goes a bit further. Engaging in an author’s ideas forces us to think through what matters to us, how we understand the world, and so on. “By discovering what authors think, feel, and care for, we find out who they are,” said Thomas L. Jeffers in The Weekly Standard. But that’s only half of it. “By entering into dialogue with their books—annotating in the margins when we agree or disagree or when we aren’t sure—we define who we are.”
Books have a way of confirming—even conferring—identity. But it’s not a passive experience. As readers, we get to clarify and object. And in that process of rejoinder we hone our understanding of ourselves.
As people, we come to knowledge of ourselves within the communities we live. No one knows who they are on their own. We live and think in relation to others. Books broaden the range of those others by including people who wouldn’t otherwise fit or belong in our social circles for reasons of chance, time, proximity, or what have you. Books expand our world and help us define who we are within it.

5. Enjoying Yourself
Finally, you should write in your books because it’s fun. In researching The Magician’s Book, Laura Miller came upon a letter by C.S. Lewis in which he describes the joy of properly inking a page. First, he describes his process:
To enjoy a book like that thoroughly I find I have to treat it as a sort of hobby and set about it seriously. I begin by making a map on one of the end-leafs: then I put in a genealogical tree or two. Then I put a running headline at the top of each page: finally I index at the end all the passages I have for any reason underlined.
Then Lewis describes the payoff:
I often wonder—considering how people enjoy themselves developing photos or making scrap-books—why so few people make a hobby of their reading in this way. Many an otherwise dull book which I had to read have I enjoyed in this way, with a fine-nibbed pen in my hand: one is making something all the time and a book so read acquires the charm of a toy without losing that of a book.
Lewis was far more systematic than am I. But I take similar joy in marking up my books. In fact, I can’t live without it. There is nothing scandalous about writing in your books. It usually improves the reading experience; in many cases it even improves the book.
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A must for reading and a delight.
Three quick examples:
I read and discussed Fleming Rutledge's book, Crucifixion, with a friend. It is 612 pages long. For my first read, I made 557 marginal notes, anything from an exclamation point to a long comment. Another friend wanted to read and discuss it with me. I wasn't sure whether I would give it a serious reread, but I did. Another 345 marginal notes were made. 912 notes. It is now a treasure trove for edification, writing, and teaching.
When I taught at Wheaton, I headed over to the Wade collection. I saw C.S. Lewis's copy of Paradise Lost, which I love. The marginalia were meticulous, small, but legible. If a man who got a triple first at Oxford thought writing in books was a good idea, who am I to disagree?
Last, and strangest example. William F. Buckley had me over to his house for a wonderful lunch. It was just the two of us and his chef. He said I could roam around. I saw a fifty-year reunion book for Yale. In it, there were pictures of Bill's classmates and of course, him. I noticed that he made notes by some of the pictures to remind himself of various things about certain persons. I'm sure no one felt the need to put a note of explanation by him!
Just not in someone else’s book or in a library or school copy! Even in my own books, if done poorly, it can limit my later experience of reading the book again. I almost need to buy another copy for a reread or to lend without embarrassment. In fact, I’m pretty sure I’ve purchased a “lending copy” of several books that sit side by side on my shelves.