The Problem That Never Goes Away
You read something remarkable. You highlight it, save the link, maybe screenshot a passage. Weeks later, you sit down to write and you cannot find it. You know you read it. You know it was good. You have no idea where it went.
This is not a new problem. It is, in fact, one of the oldest problems in intellectual history and one of the oldest solutions exists too, waiting to be rediscovered by every generation of writers and thinkers who discover it fresh. That solution is the commonplace book.
A commonplace book is a personal collection of passages, quotes, observations, and ideas gathered from reading and experience, kept in a notebook or equivalent and consulted as a resource for thinking and writing. The tradition is ancient. The practice emerged from Greek and Roman rhetorical culture, where scholars collected fragments from texts deemed useful, wise, or memorable. The Latin term was loci communes, "commonplaces of knowledge": passages and ideas considered sufficiently important to commit to memory and return to.
The standard advice for the research-disappears problem is to save more links, highlight more passages, take more notes. The sources suggest this makes things worse. More material does not help when the system for retrieving it is broken. What you need is not more capture but a better home for what you capture: a curated anthology that you can actually use when you write.
A Method Older Than the Printing Press
Commonplace books are not a modern invention. The habit is close to 2,000 years old. According to Wikipedia, "the Ancient Greeks developed hypomnema, personal records on important subjects," the earliest documented ancestor of writing down what you want to keep.
The practice kept resurfacing under different names for the next two millennia. In pre-digital times, people used many kinds of notebooks, including commonplace books, accounting waste books, and marginalia three separate habits all pointed at the same problem: catch a thought before it disappears. During the Renaissance, the practice was institutionalized as a study method in European universities: students kept hand-copied books of memorable passages from their reading, organized into topical headings.
Francis Bacon, in The Advancement of Learning (1605), recommended commonplace books with a distinctive organization: "I hold the entering of common places to be a matter of great use and essence in studying." The printing press had flooded Europe with more text than any individual could absorb. Educated people developed systematic ways to cope: notebooks filled with extracts, organised by theme, to serve as personal reference libraries.
Jonathan Swift captured the spirit of the thing in 1721: a commonplace book is something "a provident poet cannot subsist without, for this proverbial reason, that great wits have short memories." The problem the method solves is universal: you read things that change how you think, and then you forget them.
John Locke's Index: The System That Made It Work
The most systematic account of how to keep a commonplace book came from John Locke, who developed his approach over twenty-five years of personal note-taking and published it in French in 1685, with an English translation appearing posthumously in 1706.
Locke's core contribution was an indexing system. He recommended keeping two pages at the front of the book with an expandable index, a line for each letter of the alphabet and subdivisions for each vowel. When you added a new entry, you noted its page number under the relevant letter and vowel combination. This let you retrieve entries on a given topic without reading through the whole book.
We extract only those things which are Choice and Excellent, either for the matter itself, or else the elegancy of the expression, and not what comes next. John Locke, as recorded in historical accounts of his commonplace book method
The method was influential because it solved the commonplace book's main practical problem: what use is a large collection if you cannot find anything in it? Locke's index provided just enough order to locate things without imposing so much structure that the collection became rigid. Publishers started printing blank commonplace books with pre-made indexes based on his method.
According to author Nicholas Basbanes, "Locke gave specific advice on how to arrange material by subject and category, using such key topics as love, politics, or religion. Commonplace books, it must be stressed, are not journals, which are chronological and introspective."
Who Kept Them: A Gallery of Practitioners
The roster of historical commonplace book keepers reads like a tour of intellectual history. Thomas Jefferson kept extensive multi-volume collections, recording entries in English, Latin, and Greek, primarily noting favorite quotes from books he read. Mark Twain kept notebooks that fed his writing. H.P. Lovecraft kept one. W.H. Auden kept one. Ronald Reagan kept a notecard system of quotes and stories.
"Scholars, amateur scientists, aspiring men of letters just about anyone with intellectual ambition in the seventeenth and eighteenth centuries was likely to keep a commonplace book," writes Steven Johnson. "In its most customary form, 'commonplacing,' as it was called, involved transcribing interesting or inspirational passages from one's reading, assembling a personalized encyclopedia of quotations."
The most famous examples span two millennia. Marcus Aurelius kept a commonplace book that was effectively turned into the book Meditations, a core text of Stoic philosophy. Darwin kept one and used it to sketch the first diagram of evolutionary theory, scribbling "I think" in the margin above a spindly tree of life. Milton kept one. Emerson kept one. John Stuart Mill kept one. Jonathan Swift, Leonardo da Vinci (full of sketches, grocery lists, and engineering ideas all jumbled together), and Montaigne (who accidentally turned his into one of the greatest books ever written) all kept them.
Ronald Reagan used a notecard system to record stories and jokes to use in speeches. "He had all this stuff he had stored up all these years all these stories, all these anecdotes," said Reagan's speechwriter Ken Khachigan. "He had the Reagan library in his own little file system."
The Modern Practitioner: Ryan Holiday and the Stoic Connection
In the modern productivity literature, Ryan Holiday has done more than anyone to popularize the practice. He writes about Stoicism and maintains a physical card-based commonplace book. On his own site, Holiday describes a commonplace book as a repository for "ideas, quotes, anecdotes, observations and information" gathered from reading and from life, kept so it can be retrieved and reused.
Holiday's notecard system is the version most people encounter first today. It is physical (index cards more than digital), selective (only what matters goes in), and organized by theme. The physical format is intentional: writing by hand slows you down and forces selection you cannot copy everything, so you choose what matters.
E.M. Forster used his commonplace book to record quotes, comments on what he was reading at the time, interesting tidbits he overheard in others' conversations, and ideas for future novels. Erasmus (1466-1536) is known as the father of modern commonplacing, popularizing the concept in his book De Copia in 1512. He subdivided his book into categories of virtues and vices, like piety and fidelity.
Why the Method Builds Authority
Here is what the historical record shows: the practitioners who kept commonplace books consistently produced more and more credibly than those who did not. The method builds authority through several mechanisms that remain relevant for bloggers today.
First, selectivity creates depth. A commonplace book that contains everything is just a filing cabinet. A commonplace book that contains only the things that actually moved or changed you becomes, over time, a map of your intellectual development. When you write from it, you are writing from the accumulation of your best thinking, not from the anxiety of a blank page.
Second, the physical act of transcription forces engagement. When you copy a passage by hand, you are not just saving it you are inhabiting it. The pace of handwriting prevents passive consumption. You cannot copy everything, so you must decide what matters. That decision-making process is where the learning happens.
Third, the organizational structure enables retrieval. The problem is not finding ideas when you need them; the problem is finding them when you need them. Locke's index, or a card-box sorted by theme, solves the retrieval problem that undermines most research practices. Ideas you have read and copied become part of your working vocabulary. When you sit down to write about governance, or community, or creative process, the relevant passages are there not buried in a folder you forgot existed.
Fourth, the accumulation compounds over time. Thomas Jefferson's commonplace books spanned decades. Marcus Aurelius wrote Meditations over years, not days. The authority that comes from a commonplace book is not instantaneous; it is the product of sustained engagement with ideas across a long period. Fifteen years of entries represent fifteen years of intellectual development a record of growth that is difficult to fabricate and impossible to shortcut.
How to Build Your Own Commonplace Book
Setting up a commonplace book begins with choosing your medium. The traditional form is a physical notebook or index cards. A hardcover notebook (Moleskine, Leuchtturm 1917) or index card box works well. Writing by hand slows you down and forces selection you cannot copy everything, so you choose what matters.
However, any cataloging system can serve the same purpose: 3x5 cards, a digital note app, or even a text file you add to when you read something neat. The format is not what makes it a commonplace book. What makes it a commonplace book is the habit: pulling ideas, quotes, and observations out of what you read and the life you live, and putting them somewhere you can find them again later.
Locke's method remains instructive. Keep two pages at the front for an expandable index. Use a line for each letter of the alphabet with subdivisions for each vowel. When you add a new entry, note its page number under the relevant letter and vowel combination. This lets you retrieve entries on a given topic without reading through the whole book.
The instructions for what to collect are equally considered. We extract only those things which are Choice and Excellent, either for the matter itself, or else the elegancy of the expression, and not what comes next. The commonplace book is not a transcription of everything you read. It is a curated selection of the best of what you encounter.
Practical discipline is selectivity. What goes in a commonplace book? Quotes that capture something you believe or challenge something you believe. Passages that illuminate a concept more clearly than anything you have read before. Observations from your own experience that seem significant. Fragments of dialogue, poems, descriptions of places, statistics, questions you cannot answer.
Where the Ancient Practice Meets the Modern Blog
For bloggers and content creators, the commonplace book method solves a specific modern problem: the gap between reading and writing. Most bloggers read widely. Few have a system for transforming that reading into publishable material. The commonplace book provides that system.
When you keep a commonplace book, you are building a reservoir of ideas you have already processed. You have copied them, thought about them, organized them. When it comes time to write, you are not starting from zero. You are selecting from your best thinking and arranging it for a specific purpose.
This creates a content flywheel. Each entry in your commonplace book is a potential article, a citation for an argument, a frame for a concept. Over time, the flywheel accelerates. You have more material than you can use, which means you can be selective about what you publish. Selectivity creates quality. Quality creates authority. Authority attracts readers. Readers provide feedback that enriches your commonplace book further.
The method also solves the research-disappears problem that bedevils bloggers who rely on saved links and highlights. A link you saved in 2023 may be behind a paywall now, moved to a new URL, or simply lost in a folder of hundreds of other links. A passage you copied into your commonplace book in 2023 is still there, organized, and ready to use.
What This Means for BloggerPost Readers
If you are building a blog around a specific topic whether that is technology, travel, business, or any specialized subject the commonplace book method offers a path to depth that goes beyond content marketing. It is not about publishing more frequently or optimizing for search. It is about developing genuine expertise through sustained engagement with the ideas in your field.
The bloggers who build fifteen years of authority are not the ones who published most often. They are the ones who developed the deepest relationship with their subject matter. A commonplace book is the tool for developing that relationship systematically, entry by entry, over years.
The practice is simple enough to start today. Pick a notebook. Choose your first entry a quote, a passage, an observation that struck you. Copy it by hand. Add it to an index. Return to it when you write. That single entry is the first stone in a foundation that can support a decade or more of authoritative content.
Where to Read Further
For a comprehensive guide to the commonplace book method with historical context and practical steps, see WebSnips' complete guide to the Commonplace Book Method.
The Fabric guide to commonplace books offers additional perspective on the practice's evolution from classical rhetoric through modern productivity, including a detailed look at Locke's indexing system.
For a shorter introduction with a focus on getting started, InstantOwl's history and starter guide covers the 2,000-year arc of the practice and practical first steps.
The Leo guide to the commonplace book as a thinking tool traces the practice from Marcus Aurelius to Bruce Lee, emphasizing the external surface as the place where thinking actually happens.
For additional perspective on commonplacing and writing, BobbyPowers.com's how-to guide includes Steven Johnson's observation on the practice's historical prevalence among intellectual communities.