Commonplace book: what it is and how to start one

What is a commonplace book—and how is it different from a journal?

The central practice is selection: you encounter something worth keeping, record it with its origin and give yourself a way back to it. A passage from a book can sit beside a field observation, a diagram or a question from a conversation. The collection does not need to document every day or contain a finished argument. It needs to remain understandable when the moment that prompted the entry has passed.

A diary usually follows your experiences through time. A reading journal may follow one book from beginning to end. A commonplace book brings material from different sources into a collection you can revisit by topic. These boundaries are practical rather than rigid: a notebook can contain all three, provided you can distinguish a copied passage, an observation and your own response.

If you mainly need to capture a lecture or meeting, compare note taking methods first. Commonplacing is a selective second step, not an obligation to copy every rough note into a nicer book. A three-sentence entry you use is more valuable to the practice than pages of copied material you cannot locate.

A short history: Renaissance headings and Locke’s index

Commonplacing was an established early modern practice, not an invention of a contemporary app. Historian Michael Stolberg’s study of Locke and earlier commonplace methods describes pupils following Erasmus and other humanists by excerpting useful material under topics or headings. Such collections supplied material for speaking and writing; later scholars also kept observations rather than only elegant quotations.

Erasmus’s rhetoric book De copia was published in 1512, as Cuyamaca College’s educational resource records. That date belongs to his book, not to the invention of commonplacing. The relevant lesson is that collecting and organizing useful material had a place in Renaissance education; it was not simply a hobby for preserving favorite lines.

John Locke later developed a compact indexing method. His French account, Méthode nouvelle de dresser des recueils, appeared in 1686; an English version appeared in 1706. Gallaudet University catalogs the latter volume as A new method of making common-place-books. Stolberg explains its distinctive index: page numbers were grouped by a heading’s initial letter and the first following vowel. It was not simply a modern alphabetical list of every topic.

You do not have to reproduce Locke’s letter-and-vowel grid to keep a useful commonplace book. Borrow the problem he was solving: how to make room for new topics while retaining a path back to earlier entries. A growing index or a modest set of digital tags can serve that purpose without turning the notebook into an indexing project.

What to put in a commonplace book

Keep material because it is relevant to an interest, raises a good question or gives you something to work with. You do not need a list of approved subjects. Choose enough of the original context to preserve the meaning, then add your reason for saving it. The following are possible entry types, not historical rules or a quota to fill.

Passages and definitions

Copy a short excerpt accurately, mark it as quoted language and include the author, title, edition or publication date and page or location. Record a definition’s conditions, not just the memorable sentence.

Observations

Describe what you noticed, where and when. Separate an observation such as a doorway being shaded from an inference about why it was designed that way.

Images and diagrams

Include your own photograph or sketch, or a reference you have permission to retain and use. Record the creator and source where known, along with what the image helps you notice.

Ideas and questions

Write your own response, a possible connection or a question to investigate. Label an untested idea as an idea rather than as the source’s conclusion.

Practical patterns

Keep an explanation, process or example you expect to adapt. Note the situation it applies to so you do not later mistake a conditional recommendation for a universal rule.

Avoid copying an entire chapter because you cannot choose a passage. Record the chapter reference and a sentence about its usefulness instead. If a detail is easy to find again and adds nothing to your thinking, a source link may be enough. Selection is what distinguishes your collection from a second copy of the source.

Keep the source beside every excerpt

A passage without its origin becomes difficult to verify, contextualize or use responsibly. Make source details part of the entry, not a chore postponed until the notebook is full. Keep copied language visually distinct from your own paraphrase and response. If you shorten an excerpt, make the omission visible and check that it has not changed the meaning.

• Books: author, full title, edition or publication year and page number; use a stable chapter or location reference when pages are unavailable.
• Web pages: creator or organization, page title, original URL, publication date when available and your access date.
• Audio or video: creator, episode or item title, source link and the relevant timestamp.
• Your own material: date, place or project and enough context to understand what you observed. Protect private information that does not need to be retained.

For a fictional example, imagine a notebook on small public gardens. One entry contains your sketch of a sheltered bench; a separate note says you want to compare seating near entrances. You would record the visit context with the sketch, then keep any later sourced claim about seating distinct from that observation. Neither the sketch nor the adjacent thought proves a general conclusion.

A source record is not permission to republish a photograph or long excerpt. Prefer your own material, licensed references or public-domain sources when making something to share. Before using a saved passage in new work, return to the original and check its context rather than relying on a memorable fragment.

Headings, an index or tags: choose a light structure

For paper, a flexible starting structure is chronological entries with a topical index at the front or back. Number the pages and add a short heading to each entry. When you save something under “shelter,” add that heading and its page to the index. Later entries can go on the next free page instead of forcing you to predict how much room every topic will need.

Headings

Use a recognizable phrase such as “thresholds,” “revision” or “light in interiors.” A useful heading describes the material, not just the mood you were in when saving it.

Index

List the heading and all relevant page numbers. When a topic appears under more than one name, add a cross-reference so either route leads to it.

Tags

In a digital collection, choose a small vocabulary you will remember. Reuse an existing tag when it means the same thing rather than making several near-duplicates.

Dedicated sections work if you already know the subject boundaries, but a section for every imaginable topic can leave large gaps and cramped popular sections. Loose cards offer another option: one entry per card, stored by heading or linked with identifiers. Whichever structure you use, try locating an older entry before adding more categories.

When relationships matter more than a list of headings, borrow the containers and connectors in visual note-taking. Keep a word beside the connection to explain it. Two excerpts next to each other may be a useful comparison without expressing the same claim.

Analog vs a digital commonplace book

Choose paper if the practice you want is a self-contained notebook of selected entries and sketches. It offers a stable page and direct handwriting, but retrieving a forgotten phrase requires an index or browsing. A digital commonplace book suits material you want to edit, search or connect to original links. Its tradeoff is that effortless capture can create a collection larger than you will review.

A hybrid can be simple: keep the notebook as the working collection and make a digital photograph of selected pages with a typed title and source record. Do not create three competing archives unless each has a clear purpose. Decide which version is authoritative, where originals live and how you will make a backup before the collection becomes important to you.

Canvas Perch’s capture page describes collecting notes, links, images and documents in an inbox, then reviewing a capture’s title and source. That can support a digital commonplace habit where each item retains its context. Choose an available tool that meets your needs today rather than postponing the practice.

Before committing to any digital tool, test saving one passage, correcting its source, finding it later and keeping a separate copy. Review privacy and sharing settings before saving confidential material. A beautiful notebook interface is less important than a collection you can retrieve and maintain.

How to start a commonplace book with five fields

Use the same small entry structure for your first few items. It reduces decisions without prescribing the whole notebook. You can write the field names only when they help; a short heading, a marked excerpt and a clear source line may already make the structure visible.

1. Heading: the topic or question under which you expect to find this again.
2. Material: a short passage, image, observation or original idea, with its type clear.
3. Source: the complete details needed to return to the original, including page or timestamp.
4. Response: one or two sentences about why it matters, what you disagree with or what it suggests.
5. Return path: a page in the index, a tag or a cross-reference to another entry.

For the fictional garden notebook, an entry might be headed “Sheltered seating,” contain your own visit sketch and date, and include a response asking whether shelter changes how you would arrange a drawing composition. That response is yours, not a claim attributed to a nonexistent researcher. A useful entry can be modest and still lead to real work.

If you already have a pile of links, use from bookmarks to ideas to select a small starting collection. Bring over the few items you can explain rather than importing everything and calling the migration a new habit.

A weekly habit that turns collecting into use

Choose a recurring review time and a collection small enough to read during it. Look at recent entries, repair missing source details and update the index. Then select one item to use: develop a paragraph, try a drawing study, compare it with another entry or investigate the question it raised. This is a suggested routine, not a claim that a particular schedule improves learning.

• Retrieve: find one older entry without scrolling or browsing the entire collection.
• Clarify: add context where an excerpt no longer makes sense on its own.
• Connect: explain one relationship to another entry without forcing a match.
• Apply: turn one saved item into something outside the notebook.

If you want a broader system organized around ongoing work, read about a second brain. If the main aim is developing reusable linked arguments, explore Zettelkasten. You can borrow either approach without abandoning the commonplace book’s core habit: select worthwhile material, preserve its origin and return to it with your own thinking.