How to Start Commonplacing: Build Your Book of Ideas
Abdul WadoodLast updated 
A commonplace book is one of the oldest tools for thinking, and it is also one of the simplest. Long before note-taking apps, students in Renaissance Europe were taught to copy memorable passages into a personal notebook, sorted by theme, so they could find and reuse them later. The practice shaped the reading habits of some of history’s most disciplined minds, and it survives today for a practical reason: it forces a reader to decide what actually matters.
Starting one is not hard. Starting one that you will still use six months from now is harder. Most people quit because they copy too much, organize too soon, or treat the notebook as a museum instead of a workshop. This guide walks through a method that works, the mistakes that quietly kill the habit, and how commonplacing differs from the journaling and note apps you may already use.
What a Commonplace Book Actually Is
The term comes from the Latin locus communis, meaning “common place” — a general theme or argument that could be pulled into a speech or an essay. In classical rhetoric, speakers collected these building blocks in advance so they could assemble an argument on demand.
A commonplace book is therefore a curated collection of excerpts, quotations, observations, and short reflections, filed under consistent headings. It is not a diary. It is not a record of your day. It is a personal library of passages you found worth keeping, with a little of your own thinking attached.
That distinction matters more than it sounds. A journal is chronological; a commonplace book is thematic. You write in a journal to process what happened. You write in a commonplace book to capture what you want to be able to find again.
Why Bother in an Age of Infinite Bookmarks
Saving a link takes a second. Re-reading it takes intention. The gap between those two acts is where most learning quietly dies.
Commonplacing closes that gap by slowing you down at exactly the right moment. To copy a passage by hand, you have to read it closely, judge it, and decide where it belongs. That judgment is the whole point. The notebook is a by-product; the attention is the product.
There is a second benefit that surprises first-timers. Once you have a place to put good ideas, you start noticing more of them. The habit trains a kind of reading alertness that is difficult to fake and easy to lose when you read passively on a screen.
The Minimal Starter Kit
You need less than you think. A single notebook and a pen will do. Everything else is optional.
| Item | Why It Helps | Do You Need It? |
|---|---|---|
| One notebook, A5 or larger | Room for excerpts plus notes | Yes |
| A pen you enjoy | Reduces friction, oddly effective | Yes |
| Two or three index tabs | Separates sections early | Helpful |
| A loose index page | Lets you find entries later | Recommended |
| A second notebook | Splitting topics across books | Not yet |
The most common mistake at this stage is buying an elaborate system before writing a single entry. A fancy leather journal with a pre-printed index is lovely, but it also raises the stakes. If the first page feels precious, you will hesitate to fill it with imperfect notes. Start cheap. Start ugly. Start today.
Step 1: Choose a Simple Heading System
Every entry needs a home, and the home needs a name you will remember. There are two workable approaches, and both beat having no system at all.
The lettered index. This is the scheme John Locke described in a 1706 pamphlet on making commonplace books. You dedicate a page or two at the front to an index, organize headings under letters, and record the page number where each entry lives. It is fast, forgiving, and works in any blank notebook.
The thematic sections. You pick a handful of broad headings — say, Writing, Money, Health, Quotes Worth Keeping, Questions I Cannot Answer Yet — and reserve a chunk of pages for each. Simpler to browse, but it runs out of room when a topic grows.
Whichever you pick, keep the headings broad at first. A heading like “Productivity” will absorb dozens of entries. A heading like “Time-blocking tips for Tuesday mornings” will hold two and then die. You can always split a fat section later; merging a fragmented mess is much more painful.
Step 2: Read With a Pen in Hand
This is the step people skip, and it is the step that determines whether the habit survives.
Reading with a pen means you mark passages as you go rather than promising to come back. A light pencil mark in the margin is enough. The goal is not to annotate beautifully; it is to make sure that when you close the book, you know exactly which three sentences you want to keep.
A practical rule: capture no more than three passages per reading session. Copying ten quotations feels productive and almost never is. Three forces you to choose the best, and choosing is the skill you are building.
When you copy, include four things:
- The passage itself, copied exactly.
- The source — author, title, and page.
- A one-line note on why it caught you.
- The date you recorded it.
That third item is the difference between a scrapbook and a thinking tool. A quotation with no note is a fact you stored. A quotation with a note is an idea you engaged with.
Step 3: Write the Note, Not the Quote Alone
The single most useful habit in commonplacing is the reaction line. After every excerpt, write one sentence in your own words. It can be a disagreement, an example, a connection to something else you read, or a question the passage raises.
Three reaction lines that work well:
- This is true in my experience because…
- This contradicts what I read last month about…
- I want to test this the next time I…
Over a year, those reaction lines become the most valuable part of the notebook. The quotations are borrowed; the reactions are yours. When you eventually write something — an essay, a talk, a letter, a proposal — the reaction lines are where the original thinking lives.
Step 4: Build a Findable Index
A commonplace book without an index is a box of loose memories. You will remember that you wrote something brilliant about attention, and you will not find it. Then you will stop trusting the notebook, and then you will stop using it.
Keep the index simple. One or two pages at the front, entries added as you go, each one a heading plus a page number. Update it the same day you write the entry, not later. “Later” is where indexes go to die.
If you use a digital tool instead, the equivalent is consistent tagging — but resist the urge to build an elaborate taxonomy. Five to fifteen tags used consistently will outperform a hundred tags used sporadically.
Step 5: Review on a Schedule
Commonplacing pays off on the second read, not the first. A short review ritual turns a static notebook into a working one.
A schedule that holds up in practice:
- Weekly, five minutes. Flip through the week’s entries. Add any missing index lines.
- Monthly, twenty minutes. Re-read one section. Star the entries that still feel alive.
- Quarterly, an hour. Look for patterns. Which themes keep recurring? Those are the questions you are actually thinking about.
The quarterly review is where most people get their first real surprise: the topics they thought they cared about are often not the topics they kept writing down.
Common Mistakes That Kill the Habit
Copying too much. The most common failure. A notebook filled with undifferentiated quotation is a transcription exercise, not a thinking tool.
Waiting for the perfect system. There is no perfect system. There is a notebook you use and a notebook you admire. Pick the first one.
Skipping the source. An unattributed quotation is nearly useless later, and it is a genuine problem if you ever publish. Record the author, title, and page every time.
Treating it as a diary. If entries start reading like “today I felt tired and went for a walk,” the thematic structure collapses. Keep the two books separate.
Never re-reading. A commonplace book you never open is a very expensive way to feel productive.
Commonplace Book vs. Journal vs. Zettelkasten
These three practices get lumped together, and the confusion causes real friction for beginners. They are different tools with different jobs.
| Practice | Core Unit | Organization | Main Purpose |
|---|---|---|---|
| Commonplace book | Curated excerpt plus note | Thematic headings | Keep and reuse good passages |
| Journal | Dated entry | Chronological | Process experience |
| Zettelkasten | Atomic idea, one per note | Linked network | Develop original arguments |
A commonplace book sits closest to reading. A journal sits closest to living. A zettelkasten sits closest to writing. Many people keep a commonplace book for years and never need the third. Others start commonplacing and later migrate their best notes into a linked system. Both paths are fine.
Going Digital Without Losing the Point
Digital commonplacing works, but it fails in a specific way: capture becomes so easy that judgment disappears. When clipping a passage costs nothing, you clip everything.
If you go digital, keep the constraints that make the paper version effective. Limit yourself to a small number of captures per session. Write the reaction line in your own words rather than pasting a summary. Keep a stable set of tags. And schedule the review, because a digital archive is even easier to forget than a shelf of notebooks.
Some people run a hybrid: paper for reading notes, a searchable document for the index. That works well, provided the index stays current. For more on building durable content and research habits around ideas worth keeping, see Voozon Media.
A Realistic First Month
Week one: pick a notebook, choose five headings, write the index page. Read one essay and record three passages with reaction lines.
Week two: repeat. Add two new index entries. Notice which heading you are naturally drawn to.
Week three: re-read everything you have written so far. Star the entries that still feel sharp. Do not add anything new for a day.
Week four: write one paragraph in your own words that draws on at least three of your entries. This is the moment commonplacing stops being an exercise and starts being a tool.
Thirty days in, most people have somewhere between ten and twenty-five entries. That is plenty. A commonplace book is not a race; it is a slow accumulation of things you decided were worth keeping.
Conclusion
Starting a commonplace book takes an afternoon. Keeping one takes a small, repeatable ritual: read with a pen, copy sparingly, write a reaction, file it under a heading you will remember, and look back on a schedule. The system matters far less than the discipline of deciding what deserves to be kept.
The people who get the most from commonplacing are not the ones with the most beautiful notebooks. They are the ones who kept writing in an ordinary one long after the novelty wore off. Pick a notebook this week. Copy three passages. Write three sentences of your own. That is the whole beginning.
Frequently Asked Questions
How many entries should a commonplace book have?
There is no target number. Ten well-chosen entries with thoughtful reactions are worth more than a hundred copied quotations with no commentary. Focus on quality of selection rather than volume, and let the notebook grow at whatever pace your reading allows.
Can I keep a commonplace book digitally?
Yes, and many people do. The risk is that digital capture is so frictionless that you stop judging what is worth keeping. Keep the constraints that make the paper version work: limit captures per session, write reactions in your own words, use a small stable set of tags, and schedule regular reviews.
What is the difference between a commonplace book and a journal?
A journal is organized by date and records your experiences and feelings in sequence. A commonplace book is organized by theme and records passages from other sources alongside your reactions to them. Many people keep both, and keeping them separate makes each one more useful.
Do I need to copy quotations by hand?
Hand-copying slows you down, and that slowness is the point: it forces close reading and a decision about where the passage belongs. Typing works too, but only if you resist the temptation to paste large blocks of text without engaging with them.
What should I do when a section of my notebook fills up?
Start a continuation section later in the same notebook and note the new page range in your index. Avoid cramming entries into margins, which makes the notebook hard to read later. If a topic keeps overflowing, that is a signal it deserves its own dedicated notebook.
How is a commonplace book different from a zettelkasten?
A commonplace book collects curated excerpts from other people, filed by theme, with brief personal notes. A zettelkasten breaks ideas into small atomic notes written in your own words and links them into a network. The first is a reading tool; the second is a writing and thinking tool.