I own a first edition of Graham Greene’s The End of the Affair that I bought at a used bookstore in Philadelphia about twelve years ago. The previous owner, whose name I don’t know, read it with a pencil. The margins are full of their handwriting: questions, reactions, small drawings, underlined passages connected by arrows to notes on the facing page. On page 147, next to a passage about jealousy, they wrote “this is exactly it” and underlined the phrase three times. I have never met this person. I know them, in some ways, better than people I see every day.

That book, with its penciled marginalia, is one of my most prized possessions. It has given me more sustained pleasure than almost any other object I own. And it represents something that I think we’re in danger of losing: the tradition of writing in books, of treating the margins as space for conversation between reader and text. This is my love letter to that tradition, and my argument for why it matters more than most people think.

Marginalia, for the unfamiliar, refers to notes, comments, and marks made in the margins of books by their readers. The practice is as old as books themselves. Medieval monks annotated manuscripts with commentary and corrections. Renaissance scholars filled margins with cross-references and disputes. Samuel Taylor Coleridge was such a prolific marginalia writer that his notes on other people’s books have been published as a multi-volume set. Mark Twain’s marginalia was acidic, funny, and revealing of a mind that could not encounter a sentence without having an opinion about it. Edgar Allan Poe literally reviewed other writers’ work in the margins of their own books.

These aren’t just historical curiosities. They tell us something important about what reading actually is when it’s done with full engagement. Reading is not passive reception. It’s an active, creative process in which the reader’s mind interacts with the text to produce meaning that neither the text nor the reader could have generated alone. Marginalia is the visible trace of that interaction, the evidence that someone was here, thinking, reacting, arguing, being moved.

I started writing in books in college, mostly because a professor I admired told me that any book I wasn’t willing to mark up was a book I wasn’t reading seriously enough. I resisted at first. Like many people, I’d been taught to treat books as sacred objects, to be kept pristine and handled with care. Writing in a book felt transgressive, almost violent. It took me several months to get past that feeling, and when I did, my reading life changed fundamentally.

Here’s what happens when you read with a pencil in your hand. You slow down. Not dramatically, but noticeably. The pencil creates a kind of accountability. You can’t just let your eyes drift over the words in that semi-attentive mode that accounts for, if I’m honest, a lot of my casual reading. The pencil demands that you engage, that you decide whether each passage is worth marking, and that you articulate, even if only in a word or a phrase, what your reaction is. This slowing down is not a cost. It’s the benefit. It’s the thing that transforms reading from consumption into conversation.

My marginalia has a personal vocabulary that has evolved over the years. An exclamation mark in the margin means I found the sentence striking, either for its beauty or its insight. A question mark means I disagree or don’t understand. “Yes” means the author has articulated something I’ve felt but never been able to express. A squiggly line under a sentence means the prose itself is doing something interesting, rhythmically or structurally. A star means I want to find this passage again. “NB” (nota bene) means this idea connects to something else I’ve been thinking about. None of this system is particularly original. But it’s mine, and returning to a book I’ve marked up is like returning to a journal from a particular period of my life.

That last point is worth dwelling on, because I think it gets at something that highlighting on a Kindle simply cannot replicate. When I open a book I read ten years ago and see my own marginalia, I’m encountering two texts simultaneously: the author’s and my own. The notes I made reveal who I was as a reader at that specific moment in time. Sometimes I’m embarrassed by them. (My twenty-year-old self had some terrible opinions about Thomas Hardy.) Sometimes I’m surprised by them, discovering that I once had an insight I’ve since forgotten and that, reading it again, strikes me as genuinely good. The marginalia creates a record of my intellectual and emotional life that photographs and journals don’t capture, because it’s specifically tied to the act of reading, which is the act I most consistently use to think.

I want to make an argument here that might be controversial: marginalia is an act of love, not destruction. I know that many book lovers recoil at the thought of writing in books. I understand the impulse. A beautiful book, well-designed and carefully made (and we try very hard to make beautiful books at ScrollWorks), feels like something that should be preserved as it is. But a book that sits on a shelf, unread or read without engagement, is a book that isn’t fulfilling its purpose. A book with pencil marks in the margins is a book that has been lived in, wrestled with, made personal. The marks are evidence that the book did its job.

There’s a wonderful essay by the philosopher Mortimer Adler, written in 1941, called “How to Mark a Book.” Adler makes the case that there are two kinds of book ownership: having a book on your shelf and having a book in your mind. Marginalia, he argues, is the bridge between the two. I think he’s right, and I think the argument has only gotten stronger in the decades since he made it, as the sheer volume of reading material available to us has increased to the point where passive, un-engaged reading is the default mode for most people most of the time.

The rise of digital reading has complicated this conversation in interesting ways. E-readers allow highlighting and note-taking, and these features are popular; Amazon reports that millions of Kindle users highlight passages regularly. But there’s something qualitatively different about digital marginalia and handwritten marginalia that I want to try to articulate.

Handwritten marginalia is physical, spatial, and personal. The handwriting itself carries meaning. A note written in confident, large letters feels different from one squeezed into the corner of a margin in tiny script. The placement of a note, whether it’s next to the relevant passage or jammed at the bottom of the page because you ran out of room, tells you something about the reader’s engagement and process. Over time, the pencil marks become part of the book’s physical character, as much a feature of the object as the binding or the typography.

Digital highlights, by contrast, are uniform, disembodied, and impermanent. They look the same regardless of the reader’s emotional state when they were made. They’re stored in a database somewhere, detached from the physical act of reading. They can be deleted. They don’t age. They don’t have handwriting. They’re useful as a retrieval tool, certainly. But they lack the intimate, personal quality that makes handwritten marginalia feel like a conversation with your past self.

I’m not making an anti-technology argument here. I read on a Kindle sometimes, and I highlight when I do. But I notice that the books I read digitally leave a lighter impression on my memory than the books I read in print and annotate by hand. This might be a personal quirk. But research on the “haptic” qualities of reading, the way physical engagement with a book affects comprehension and retention, suggests that there’s something real happening here, something connected to the hand-brain pathway that typing and tapping don’t activate in the same way.

Let me talk about the social dimension of marginalia, because this is where it gets really interesting. Used books with marginalia are a form of accidental communication between strangers. When I bought that Graham Greene novel in Philadelphia, I entered into a one-way conversation with its previous owner. Their notes revealed what moved them, what confused them, what they cared about. I found myself agreeing with some of their observations and arguing with others. At one point they wrote “too Catholic” in the margin, which made me laugh because Greene’s Catholicism is so central to the novel that objecting to it is a little like complaining that the ocean is too wet. But the note told me something about this person, about their intellectual limits, their preferences, their blind spots. Reading a book through someone else’s marginalia is the literary equivalent of walking through someone else’s house. You learn about them whether they intended you to or not.

Some of the most valuable research materials in literary studies are annotated books from the personal libraries of writers. Knowing what Virginia Woolf underlined in her copy of Montaigne tells us something about her intellectual formation that no biography can capture. Herman Melville’s marginalia in his copies of Shakespeare reveals the specific passages and ideas that fed into Moby-Dick. These annotated books are primary sources, windows into creative processes that would otherwise be invisible.

I sometimes think about what happens to my own annotated books after I’m gone. My children will presumably inherit my library, and they’ll find, in the margins, a record of their father’s reading life that spans decades. The thought is a little mortifying (do I really want them to know how many times I’ve re-read certain novels?) but also comforting. The marginalia will be there long after I’m not, a trace of a mind engaging with the words that mattered most to it.

For anyone who wants to start writing in books but feels inhibited, here’s my practical advice. Start with a pencil, not a pen. Pencil feels less permanent and therefore less intimidating. Use a soft lead, 2B or softer, which leaves a dark enough mark to see but doesn’t dig into the paper. Start by just underlining passages that strike you. You don’t have to write full sentences in the margins. A checkmark, a question mark, a single word is plenty. The goal isn’t to produce a scholarly apparatus. It’s to create a record of your attention.

And if you’re still uncomfortable writing in books, at least consider the dog-ear. I know this is another line in the sand for book purists, but a dog-eared page is a page you wanted to return to, and wanting to return is the highest compliment a reader can pay. Some of my favorite books have corners so worn from repeated dog-earing that the pages have become soft and rounded, like stones in a river. Those worn corners tell a story about how much the book has been loved, and I’d rather have a battered, loved book than a pristine, neglected one every time.

At ScrollWorks, we make books to be read, not preserved. We choose paper that takes pencil well. We set generous margins that have room for notes. We want our books to be lived in, argued with, returned to. When I hear that a reader has written in one of our books, I feel a particular kind of satisfaction. It means the book did what it was supposed to do. It started a conversation that is still going on, in the margins, long after the last page was turned.

There’s a used bookstore in my neighborhood that has a section labeled “annotated copies.” The owner started it as a joke, setting aside the books with the most interesting marginalia, and it became one of the most popular sections in the store. Customers browse the annotations as much as they browse the books. They like seeing how other people read. They like the intimacy of it, the sense of eavesdropping on someone else’s encounter with a text. I think that tells you everything you need to know about why marginalia matters. Reading is a private act. Marginalia makes it communal, one reader reaching across time and space to another, saying: I was here, and this mattered to me.

So this is my love letter, not just to marginalia, but to the kind of reading that marginalia represents: slow, attentive, personal, and endlessly renewable. The book on your nightstand is not a museum piece. It’s an invitation. Pick up a pencil and accept it.