The Marginalia Tradition: Why Notes in the Margins Matter More Than Ever

There’s a word for the small notes people write in the edges of books. Marginalia.

It’s one of my favorite words in English. It sounds like what it is, slightly elaborate, slightly old-fashioned, a little Latinate, a little aristocratic. Marginalia. The notes at the margin.

I’ve been thinking about marginalia a lot recently, because I built an app called Margin, and people sometimes ask where the name came from. The name came from the tradition. So here is the tradition.

This is an essay about the history of writing in the margins of books, what it’s for, what it does, why some of the most interesting people in history were obsessed with it, and why I think the habit matters more in 2026, not less, than it did in the era of paper.

Medieval monks and the first margins

The marginal note didn’t begin with a reader. It began with a copyist.

When manuscripts were hand-copied in monasteries, the scribes left wide margins on the page. Officially this was for ornamentation, illuminated borders, decorative capitals, sometimes whole little paintings (marginalia in the original art-history sense). Unofficially, the margins became a place where the scribes started to talk.

You can read these notes today, in the British Library’s manuscript collection, and they are startlingly human. A scribe complains about the cold. Another grumbles about the wine. A third, in the 12th century, writes in Old Irish: “New parchment, bad ink. O, I say nothing more.” These are the first marginal notes, and they’re complaints about working conditions.

What strikes me about these earliest margins is that they’re unauthorized. The scribes weren’t supposed to be writing in the margins. They were supposed to be copying. The margin was an opportunity that emerged because there was space, and humans, given space, will say something.

This is the founding principle of marginalia: it appears where there is room to say something unofficial about an official text. The margin is always slightly subversive. It is the reader (or the scribe) refusing to be silent in the presence of the work.

Coleridge, the patron saint of marginalia

Skip forward six centuries.

Samuel Taylor Coleridge, the English Romantic poet, was a notorious marginalia writer. He wrote in everyone’s books, his own, his friends’, borrowed books he never returned. Charles Lamb famously complained that Coleridge’s annotations in borrowed books were so extensive that they became more valuable than the books themselves.

This is where the tradition shifts from complaint (the medieval monks) to commentary. Coleridge wasn’t writing in the margins to vent. He was writing because reading, for him, was a conversation. The book said something; he wanted to respond. The margin was the channel.

What’s beautiful about Coleridge’s marginalia, which survives in volume, they’ve been collected and published, is how alive it is. He argues. He sneers. He agrees with sudden warmth. He extends. He doubts. He writes No no no next to a sentence and then, two pages later, Yes, this is right after all. The margins are where Coleridge is most himself: less polished than his published prose, more reactive, more honest.

The word “marginalia,” in fact, was coined to describe Coleridge’s notes. He’s the one we got the modern sense of the term from.

Karl Marx’s library

Marx was another famous annotator. The British Library still has volumes from his personal library at the Reading Room he used for thirty years, and the marginalia is its own form of scholarship.

What Marx did, and what scholars of Marx still do, was use the margin as a way of reading actively. He’d underline. He’d write counter-arguments. He’d note connections between writers who had nothing else linking them. The margin was his thinking space, the place where the books he read became the books he wrote. Capital didn’t come from nowhere. It came from thirty years of margin notes.

I think about this every time someone tells me they “don’t take notes.” If you don’t take notes, you’re consuming. If you take notes, you’re working, even when you’re not aware that you are.

Susan Sontag and the modern margin

Closer to our time: Susan Sontag.

Sontag was, by her own admission, an obsessive marginalia writer. The UCLA archives that hold her papers contain hundreds of books from her personal library, each one densely annotated. She underlined. She circled. She wrote single-word reactions, yes, no, !, false, cf. Adorno, and full-paragraph rebuttals.

What’s interesting about Sontag’s marginalia is that you can watch her develop ideas in the margins of other writers. You can see On Photography taking shape in the annotations she made in books by Walter Benjamin and Roland Barthes years before she wrote her own essays. The margin was the place where her thinking happened first, in dialogue, with the dead.

Reading Sontag’s annotations now, you realize that her famous essays, the ones that feel like single coherent voices, were actually the output of a much longer process of arguing with other people in the margins of their books. The published essay is the iceberg. The marginalia is the underwater part.

Why marginalia matters

I want to make the case, briefly, for why this tradition matters, not just historically, but practically.

Marginalia does four things that almost nothing else does:

1. It marks attention. When you underline a sentence or write a note next to it, you’re declaring this. This is the part. That declaration is itself a small intellectual act. Without it, the text washes through you. With it, the text becomes structured.

2. It enables return. A book you’ve annotated is a different book the second time you read it. Your past self has left a map. You can flip to the margins and recover what you thought before, which means you can compare it to what you think now. Books without marginalia are flat. Annotated books have depth.

3. It generates writing. Sontag, Marx, Coleridge, none of them would have written what they wrote without the margins. The marginalia is the rough draft. The notes you take while reading are how your future essays start.

4. It changes the read. This is the subtle one. When you know you’re going to mark the book, you read differently. You’re listening for the sentences worth marking, the ideas worth disagreeing with. The act of marking sharpens what you notice. You become a better reader because you’re prepared to respond.

What happened to marginalia

For most of the 20th century, marginalia continued, pencil in hand, paperback open. The tradition was healthy.

Then digital reading happened, and marginalia mostly broke.

E-readers and apps technically let you “highlight,” but the highlights live in a place you never go back to. There’s no margin to write in, just a small popup with a yellow color picker. You can’t doodle. You can’t cross things out. You can’t write No no no in capitals along the side of a paragraph. The infrastructure of marginal commentary, which had survived a thousand years, was replaced by a button.

Most people who switched to digital reading stopped annotating, even if they kept “highlighting.” The two are not the same. A highlight says this is interesting. Marginalia says this is interesting and here is what I think about it. The difference is the difference between bookmarking a webpage and writing a blog post about it.

We lost something in that transition. We’re still losing it.

The new margin

Here is the thesis of this essay, which is also the thesis of Margin.

The marginalia tradition is alive. It was always going to be alive, because the impulse it serves, I want to mark this, I want to respond to this, I want to find this again, is a permanent human impulse. The form just had to find a new medium.

I think the new medium is voice notes attached to podcasts.

Here’s why: podcasts are the longform medium of the 2020s in the same way books were the longform medium of the 1800s. They’re long enough to develop an idea. They contain quotable moments. They make you stop. They make you want to respond. The conditions for marginalia are exactly the same as they were for Coleridge, a text moving forward, a listener who wants to mark a moment, a desire to come back later and find it.

The form is just different. Instead of pencil and margin, it’s press and hold and speak. The book is the episode. The page is the timestamp. The pencil mark is the voice note. The result, structurally, is the same: a personal layer of attention overlaid on a published work, retrievable later, generative for the listener.

Margin (the app) is my attempt to make this gesture as easy as making a pencil mark in a paperback. One press, three seconds, done. No tax. No interface to navigate. Just the marking layer.

Some closing notes

If you’re skeptical that podcast voice notes are “real” marginalia, consider what the medieval monks would have thought of pencil-in-margin annotations. The form changes. The function persists.

If you take this essay seriously, here’s what I’d encourage:

1. Start marking the podcasts that move you. Voice memo, app, paper notebook, whatever, but mark them.
2. Save them somewhere they’re retrievable, attached to the episode and timestamp.
3. Re-read your own marginalia, in the way Sontag re-read hers. The most interesting things you’ve ever thought are in the margins of other people’s work.
4. Write from the marginalia. Sontag’s essays, Marx’s Capital, Coleridge’s criticism, all started as marginal notes. Your essays could too.

The margin is where reading and listening become thinking. We didn’t stop needing the margin when the books became audio. We just needed someone to build a new one.

I hope I built it.

Selinay