What Is Marginalia?
Marginalia, in its simplest form, is anything a reader writes in the margins of a text. Notes. Questions. Objections. Doodles. Obscenities. Prayers. The word covers it all.
But that definition doesn't capture what marginalia actually represents. At its core, marginalia is evidence that someone was here, reading this, and had something to say about it. Every underline, every scribbled "YES!" or "wrong!", every little pointing finger drawn in ink beside a passage is proof that reading has never been a passive activity. People don't just receive texts. They argue with them, build on them, and sometimes deface them in creative ways.
The history of marginalia is really the history of active reading. And active reading, as research on the science of highlighting confirms, is one of the most effective ways to learn. The monks who glossed their Bibles in the 9th century and the student who highlights a web article with Glasp today are doing the same thing: processing text by marking what matters.
Medieval Marginalia: Monks, Manicules, and Monsters (9th-15th Century)
The Collaborative Manuscript
Before printing, every book was a handwritten manuscript. Creating one took months or years of labor. Books were rare, expensive, and shared. A single copy of a theological text might pass through dozens of hands over a century, and each reader could add their own layer of commentary.
This made medieval reading inherently collaborative. A monk in the 9th century might copy a passage from Augustine. A reader in the 10th century might add a Latin gloss explaining a difficult word. A 12th-century scholar might write a longer commentary in the margins debating the interpretation. By the time a manuscript had circulated for two hundred years, the margins could contain as much text as the original work.
These layered annotations, called "glosses," were so valued that they became part of the textual tradition itself. The Glossa Ordinaria, a standard set of biblical commentaries assembled in the 12th century, started life as marginal notes and interlinear comments. Eventually, printers produced editions where the original biblical text sat in a small box at the center of the page, surrounded by commentary that took up most of the space. The margins had eaten the text.
The Manicule: A Pointing Hand Across Centuries
Among the most recognizable medieval marginalia is the manicule (from the Latin manicula, meaning "little hand"). It's exactly what it sounds like: a drawing of a hand with an extended index finger, pointing at a passage the reader considered important.
Manicules appear in manuscripts dating to at least the 12th century, though some scholars trace them earlier. William Sherman, in Used Books: Marking Readers in Renaissance England (2008), documented thousands across centuries of English texts. They varied wildly in style: crude stick-figure hands, elaborately drawn versions with ruffled sleeves and visible fingernails, even exaggerated fingers that stretched across the entire margin.
The manicule served the same purpose as a modern highlight: "Look here. This is the important part." If you've ever used multiple highlight colors to mark key passages while reading online, you're doing what medieval readers did with ink and quill, just faster.
Here's the remarkable part: the manicule never died. It evolved. When early computer interface designers needed an icon to indicate a clickable link, they chose a pointing hand. The cursor that hovers over every hyperlink on the internet is a direct visual descendant of a symbol monks drew in manuscripts 800 years ago.
Monsters in the Margins
Not all medieval marginalia was scholarly. Manuscripts from the 13th through 15th centuries are full of bizarre, funny, and sometimes obscene drawings in the margins. Knights fighting giant snails. Rabbits wielding swords. Monks playing instruments while riding fish. Bare-bottomed figures in unexpected situations.
These "grotesques" or "drolleries" have fascinated historians. Some were probably the work of bored scribes. Others may have been intentional decorations, inside jokes, or commentary on the text. An Atlas Obscura feature on medieval marginalia catalogs dozens of examples ranging from the absurd to the genuinely unsettling.
Whatever their purpose, these doodles remind us that readers have always brought their whole selves to texts. The monk who drew a rabbit jousting a dog in the margin of a prayer book was doing something recognizably human: he was bored, or amused, or procrastinating.
The Print Revolution Changes Everything (15th-17th Century)
From Shared Manuscripts to Personal Books
Gutenberg's printing press, introduced around 1440, changed almost everything about how people interacted with texts. Before printing, a scholar might encounter a few hundred books in a lifetime. By the early 1500s, millions of printed volumes were circulating across Europe.
This had a contradictory effect on marginalia. More people owned books, so more people could write in them freely. But the shift from shared manuscripts to personal copies gradually moved annotation from a communal activity to a private one. In manuscript culture, your notes were part of the text's living tradition. In print culture, your notes were just yours, sitting on your shelf, seen by nobody unless you lent the book out.
Erasmus and the Humanist Annotators
The early print era produced some of history's most dedicated marginalia writers. The humanist scholars of the Renaissance treated annotation as an intellectual discipline. Desiderius Erasmus, the Dutch philosopher and theologian, was a relentless annotator. He read with a pen always in hand, marking passages, cross-referencing sources, and writing miniature essays in the margins.
Erasmus didn't just annotate for himself. He published annotated editions of classical and biblical texts, making his marginal commentary available to thousands of readers through print. In a sense, he was doing what Glasp's community feed does today: sharing his reading notes publicly so others could benefit from his expertise.
Gabriel Harvey's Famous Margins
The Elizabethan scholar Gabriel Harvey left behind some of the most studied marginalia in English literary history. Harvey annotated his books obsessively, filling margins with commentary that ranged from literary criticism to political gossip to personal ambition. His copy of Livy's Ab Urbe Condita contains hundreds of marginal notes connecting ancient Roman history to contemporary Elizabethan politics.
Harvey's annotations reveal how active reading worked for a Renaissance intellectual. He didn't just consume texts; he interrogated them, connected them to other sources, and applied them to his own career. Virginia Woolf later wrote about Harvey's marginalia, observing that his notes transformed his books into "a kind of mental gymnasium."
What's striking about Harvey is how public his practice was. He shared annotated books with friends, expected them to read his notes, and sometimes addressed marginal comments directly to specific people. His margins were a social space. That impulse, the desire to share what you've marked and thought about, is the same one that drives people to learn in public today.
The Golden Age of Marginalia (18th-19th Century)
Coleridge Gives It a Name
Samuel Taylor Coleridge was, by most accounts, a terrible borrower of books. He borrowed constantly, returned slowly (if at all), and filled other people's books with extensive handwritten notes. His friends complained. His publishers despaired. But his margin notes were so brilliant that after his death, they were collected and published as a standalone literary work.
Coleridge is widely credited with popularizing the word "marginalia" in English. He used it as the title for his collected margin notes, published posthumously in 1836. Before Coleridge, people had been writing in margins for centuries, but they didn't have a single elegant word for the practice. He gave them one.
Coleridge's marginalia wasn't casual. His notes could run for pages, filling every available white space and continuing onto slips of paper tucked between pages. He argued with authors, proposed alternative theories, and occasionally wrote poetry in the margins of other people's poetry. H.J. Jackson, in her definitive study Marginalia: Readers Writing in Books (2001), calls Coleridge "the king of marginalia" and notes that his annotations often surpassed the original texts in insight.
He treated every book as a conversation partner. His margins were where he did some of his best thinking. This aligns with what research on how to annotate shows: writing responses to a text forces deeper processing than reading alone.
John Adams Argues with His Books
Across the Atlantic, American president John Adams was conducting his own war in the margins. Adams owned a library of roughly 3,500 volumes, and he annotated them ferociously. His notes were combative, opinionated, and sometimes profane. When he disagreed with a philosopher, he didn't just note his objection. He called authors "fools," scrawled "Nonsense!" in large letters, and occasionally scribbled multi-paragraph rebuttals.
Adams' annotated library, now preserved at the Boston Public Library, offers a remarkable window into how a political mind engaged with Enlightenment thought. His margins reveal his intellectual process: which arguments persuaded him, which enraged him, where he changed his mind over time. Some books show multiple layers of annotation from different periods of his life, with the older Adams sometimes disagreeing with his younger self.
This is exactly the kind of intellectual legacy that the idea of smart notes tries to capture. Adams didn't just read. He left a record of his thinking that outlived him by centuries.
Marginalia as Intellectual Discourse
The 18th and 19th centuries represent something like a golden age for marginalia. Literacy rates were rising. Books were becoming more affordable but were still expensive enough that people treated them as important objects worth engaging with deeply. The culture encouraged active, argumentative reading.
William Blake filled the margins of Joshua Reynolds' Discourses with furious disagreements. Charles Darwin marked up books on geology and biology with questions that would shape On the Origin of Species. Mark Twain's annotated library reveals his sardonic wit applied to everything from history to religion.
In this era, marginalia functioned almost like a slow-motion intellectual social network. Scholars read each other's annotated books. Margin notes sparked correspondence. Published annotations (like Coleridge's) let a wider audience join the conversation.
The Long Decline: Don't Write in That Book (19th-20th Century)
Books Get Cheap, Margins Get Empty
The industrialization of printing in the 19th century made books dramatically cheaper. Paperback editions, serialized novels, mass-market publishing: by the late 1800s, books were accessible to nearly everyone in the developed world. This was, on balance, wonderful. But it had an unintended side effect on marginalia.
When books were expensive and cherished, annotating them felt like a natural extension of reading. You invested in a book; you engaged with it. When books became cheap and disposable, the culture around them shifted. The rise of public libraries, which began in earnest in the mid-1800s, introduced a new norm: books are shared property, and writing in shared property is vandalism.
Libraries enforced strict rules against marking books. Schools followed. Parents told children not to write in their textbooks (especially if those textbooks had to be returned or passed down). Within a few generations, the dominant cultural message flipped. Annotation went from "this is how serious readers engage with texts" to "this is how careless people damage books."
The 20th Century: Private Highlights, Public Silence
The taboo persisted through the 20th century. Even among serious readers, annotation became essentially private. You might underline passages in a book you owned, but you'd feel slightly guilty about it. University students developed elaborate highlighting systems with multiple colors (a practice backed by research on the science of highlighting). Some scholars, following Coleridge's tradition, published annotated editions. But for most readers, the social dimension had disappeared. Your highlights stayed in your book. Nobody saw what you'd marked.
The fluorescent highlighter pen, invented in 1963 by Carter's Ink Company, gave readers a new tool. But it didn't change the fundamental isolation. You could highlight more visibly and more easily than ever before. You just couldn't share those highlights with anyone.
The Digital Renaissance of Annotation (1990s-Present)
Early Digital Annotation
The World Wide Web, from its very beginning, was conceived as an annotatable medium. Tim Berners-Lee's original vision included the ability to annotate any page. That feature didn't make it into the first browsers, but the idea never went away.
Early experiments appeared in the late 1990s. The W3C launched the Annotea project in 1999, aiming to build annotation into the web's infrastructure. Third Voices, a startup from 1998, let users attach virtual sticky notes to web pages. These tools were clunky and ahead of their time, but they pointed toward something important: the web could make annotation social again.
Amazon's Kindle, launched in 2007, opened another front. It let users highlight passages and, crucially, aggregated those highlights across all readers. The "popular highlights" feature was the first mass-market implementation of social annotation. Suddenly, you could see what thousands of other readers found important in the same book.
The Rise of Web Highlighting
The 2010s saw an explosion of web annotation tools. Hypothesis built an open-source annotation layer for the web. Browser extensions began offering ways to highlight and save web content.
Glasp represents the most social evolution of this trend. As a web highlighter that makes annotations public by default, Glasp does something that would have felt natural to a medieval scribe or a Renaissance humanist: it treats annotation as a communal activity. When you highlight a passage with Glasp, other readers can see it, build on it, and discover articles through your reading activity. This is collective intelligence applied to reading, and it works for the same reason medieval glosses worked: seeing what other thoughtful readers consider important makes everyone a better reader.
Glasp also bridges different reading contexts. With Kindle highlights import, readers can bring book annotations into the same system as web highlights. YouTube Summary extends annotation to video. The boundaries between formats dissolve, and what remains is a unified record of what you've read, watched, and found worth marking.
The Manicule Becomes the Cursor
There's a small detail that ties the whole thousand-year arc together. When you move your mouse over a clickable link, your cursor changes from an arrow to a pointing hand. That hand, with its extended index finger, is a manicule.
The cursor hand icon was introduced in the early days of graphical user interfaces. Its designers chose a pointing hand because the gesture is universally understood: "look here, click here, this is important." They may or may not have known they were borrowing a symbol medieval scribes used for exactly the same purpose 800 years earlier. The manicule said, "This passage matters." The cursor hand says, "This link goes somewhere." The technology changed. The human gesture stayed the same.
Annotation Methods Across the Ages
| Era | Period | Primary Tool | Medium | Social Dimension | Who Annotated |
|---|---|---|---|---|---|
| Medieval | 9th-15th c. | Quill and ink | Parchment manuscripts | Highly social; multiple readers annotated shared texts over decades | Monks, scribes, scholars |
| Early Print | 15th-17th c. | Pen and ink | Printed books | Semi-social; annotated books shared among intellectual circles | Humanist scholars, students, clergy |
| Enlightenment | 18th-19th c. | Pen and pencil | Printed books | Mixed; some published annotations, but mostly private | Writers, politicians, scientists, general readers |
| Modern Decline | Late 19th-20th c. | Pencil, highlighter pen | Mass-market books, library copies | Almost entirely private; annotation becomes taboo in shared books | Students (reluctantly), some scholars |
| Digital Renaissance | 1990s-present | Browser extensions, e-readers, apps | Web pages, e-books, PDFs, video | Increasingly social; platforms like Glasp make highlights public | Anyone with a browser |
The table makes a pattern visible. Annotation started social, went private, and is now coming back around to social again. The thousand-year arc bends back toward its starting point, but at a scale the monks could never have imagined.
What Marginalia Teaches Us About Reading
Reading Was Never Passive
The history of marginalia demolishes the idea that reading is or should be passive. For most of recorded history, readers were also writers. They talked back to texts, questioned them, extended them. The "passive reader" is a relatively modern invention, and not a healthy one.
Research consistently shows that active engagement improves comprehension and retention. The medieval monk writing a gloss was encoding information more deeply than someone who merely read it. The Enlightenment scholar who wrote "Nonsense!" in the margin was forcing himself to articulate his disagreement, which deepened his understanding. Modern readers who annotate thoughtfully experience the same benefits.
Sharing Makes Annotation Better
The most interesting periods for marginalia, the medieval manuscript era and the current digital era, share one trait: social annotation. When people know their notes will be seen by others, they annotate more carefully. When readers can see what others highlighted, they discover insights they'd have missed alone.
H.J. Jackson observed in Marginalia (2001) that readers who annotated "for an audience" produced higher-quality notes than those who annotated purely for themselves. You think harder about what to mark when someone else might read your marks. This is one of the core insights behind learning in public: sharing your thinking, even informally, sharpens it. Medieval scribes knew this instinctively. Modern tools are rediscovering it.
The Tools Change, the Impulse Doesn't
Quill, pencil, highlighter pen, browser extension. The tools have changed beyond recognition. But the underlying impulse hasn't: "I want to mark this. I want to remember this. I want to tell someone about this."
That impulse is fundamental to how humans process information. We understand through interaction. We remember through engagement. We learn best when we leave traces of our thinking.
The manicule in a 12th-century manuscript and the Glasp highlight on a 2026 web article are separated by nine centuries of technological change. But they express the same thing: a reader saying, "This. Right here. This is worth your attention."
Frequently Asked Questions
Who coined the word "marginalia"?
Samuel Taylor Coleridge is widely credited with popularizing the term "marginalia" in English. He used it as the title for his extensive collection of margin notes, published posthumously in 1836. Coleridge was a prolific annotator who filled hundreds of borrowed books with lengthy, insightful comments. Before him, the practice existed but lacked a single, elegant name. The word comes from the Latin marginalis, meaning "of the margin."
What is a manicule?
A manicule (from Latin manicula, "little hand") is a drawing of a hand with a pointing index finger, used in the margins of manuscripts and printed books to draw attention to important passages. Manicules appear in documents dating to at least the 12th century and were widely used through the 18th century. They varied enormously in style, from crude outlines to elaborately detailed hands with cuffs and fingernails. The manicule is considered the ancestor of the pointing hand cursor icon used on computer screens today.
Why did people stop writing in books?
The rise of mass-market publishing in the 19th century made books cheaper and more widely available. At the same time, the growth of public libraries introduced strict norms against writing in shared books. Schools reinforced this by requiring students to keep textbooks clean for future use. Over time, annotation shifted from being a respected intellectual practice to something frowned upon. The "don't write in books" norm was primarily a response to books becoming shared or resalable commodities rather than personal intellectual tools.
How are digital highlighting tools like Glasp connected to the history of marginalia?
Digital highlighting tools are the direct descendants of a thousand-year tradition. They solve the two biggest problems that marginalia faced in the 20th century: isolation (your highlights were trapped in your physical book) and the taboo against marking shared texts (you can't deface a web page). Tools like Glasp bring annotation back to its social roots by making highlights visible to other readers, much like the communal manuscripts of the medieval period. They also add capabilities that physical marginalia never had: search, organization, cross-referencing with smart notes, and AI-powered summaries of highlighted content.
Conclusion: The Margins Are Alive
A thousand years ago, a monk dipped his quill in ink and drew a tiny pointing hand next to a line of scripture he thought was important. He probably didn't think of himself as starting a tradition. He was just reading actively, marking what mattered, and leaving a trace for the next person who'd pick up that manuscript.
That impulse, the urge to highlight, annotate, and share, has survived the invention of the printing press, the rise and fall of cheap paperbacks, the birth of the internet, and the arrival of AI. It survived because it's not about any particular technology. It's about how humans read. We read with our hands as much as our eyes. We need to mark, to point, to say "here."
The tools have changed enormously. Parchment gave way to paper, which gave way to screens. Quills became pencils, which became highlighter pens, which became browser extensions. But the margin, that space where readers talk back to texts, has never disappeared. It's just moved.
Today, platforms like Glasp are doing something that would have been instantly recognizable to a 12th-century scholar: they're making the margins social again. They're letting readers see what other readers find important. They're building a collective layer of attention and insight on top of the texts we all share.
The manicule became the cursor. The gloss became the highlight. The monastic scriptorium became the internet. But the reader, reaching for a way to say "this matters," hasn't changed at all.