The other day I was reading a book and I came across a little anecdote. It was about the great Athenian general Themistocles. Before the battle of Salamis, he was locked in a vigorous debate with a Spartan general about potential strategies for defeating the Persians. Themistocles was clearly in the minority with his views (but which ultimately turned out to be right and saved Western Civilization). He continued to interrupt and contradict the other generals. Finally, the Spartan general threatened to strike Themistocles if he didn’t shut up and stop. “Strike!” Themistocles shouted back, “But listen!”

When I read this, I immediately began a ritual that I have practiced for many years–and that others have done for centuries before me–I marked down the passage and later transferred it to my “commonplace book.” Why? Because it’s a great line and it stood out to me. I wrote it down I’ll want to have it around for later reference, for potentially using it in my writing or work, or for possible inspiration at some point in the future.

In other posts, we’ve talked about how to read more, which books to read, how to read books above your level and how to write. Well, the commonplace book is a thread that runs through all those ideas. It what ties those efforts together and makes you better at each one of them. I was introduced and taught a certain version of this system Robert Greene and now I am passing along the lessons because they’ve helped me so much.

What is a Commonplace book?

A commonplace book is a central resource or depository for ideas, quotes, anecdotes, observations and information you come across during your life and didactic pursuits. The purpose of the book is to record and organize these gems for later use in your life, in your business, in your writing, speaking or whatever it is that you do.

Some of the greatest men and women in history have kept these books. Marcus Aurelius kept one–which more or less became the Meditations. Petrarch kept one. Montaigne, who invented the essay, kept a handwritten compilation of sayings, maxims and quotations from literature and history that he felt were important. His earliest essays were little more than compilations of these thoughts. Thomas Jefferson kept one. Napoleon kept one. HL Mencken, who did so much for the English language, as his biographer put it, “methodically filled notebooks with incidents, recording straps of dialog and slang” and favorite bits from newspaper columns he liked. Bill Gates keeps one.

Not only did all these famous and great individuals do it. But so have common people throughout history. Our true understanding of the Civil War, for example, is a result of the spread of cheap diaries and notebooks that soldiers could record their thoughts in. Art of Manliness recently did an amazing post about the history of pocket notebooks. Some people have gone as far as to claim that Pinterest is a modern iteration of the commonplace book.

And if you still need a why–I’ll let this quote from Seneca answer it (which I got from my own reading and notes):

“We should hunt out the helpful pieces of teaching and the spirited and noble-minded sayings which are capable of immediate practical application–not far far-fetched or archaic expressions or extravagant metaphors and figures of speech–and learn them so well that words become works.”

How to Do It (Right)

–Read widely. Read about anything and everything and be open to seeing what you didn’t expect to be there–that’s how you find the best stuff. Shelby Foote, “I can’t begin to tell you the things I discovered while I was looking for something else.” If you need book recommendations, these will help.

-Mark down what sticks out at you as you read–passages, words, anecdotes, stories, info. When I read, I just fold the bottom corners of the pages. If I have a pen on me, I mark the particularly passages I want to come back to. I used to use flag-it highlighters, which can be great.

-Again, take notes while you read. It’s what the best readers do, period. it’s called “marginalia.” For instance, John Stuart Mill hated Ralph Waldo Emerson, and we know this based on his copies of Emerson’s books where he made those (private) comments. You can also see some of Mark Twain’s fascinating marginalia here. Bill Gates’ marginalia is public on a website he keeps called The Gates Notes. It’s a way to have a conversation with the book and the author. Don’t be afraid to judge, criticism or exclaim as you read.

-Wisdom, not facts. We’re not just looking random pieces of information. What’s the point of that? Your commonplace book, over a lifetime (or even just several years), can accumulate a mass of true wisdom–that you can turn to in times of crisis, opportunity, depression or job.

-But you have to read and approach reading accordingly. Montaigne once teased the writer Erasmus, who was known for his dedication to reading scholarly works, by asking with heavy sarcasm “Do you think he is searching in his books for a way to become better, happier, or wiser?” In Montaigne’s mind, if he wasn’t, it was all a waste. A commonplace book is a way to keep our learning priorities in order. It motivates us to look for and keep only the things we can use.

-After you finish the book, put it down for a week or so. Let it percolate in your head. Now, return to it and review all the material you’ve saved and transfer the marginalia and passages to your commonplace book.

-It doesn’t have to just be material from books. Movies, speeches, videos, conversations work too. Whatever. Anything good.

-Actually writing the stuff down is crucial. I know it’s easier to keep a Google Doc or an Evernote project of your favorite quotes…but easy has got nothing to do with this. As Raymond Chandler put it, “when you have to use your energy to put those words down, you are more apt to make them count.” (Disclosure: for really long pieces, I’ll type it up and print it out).

-Technology is great, don’t get me wrong. But some things should take effort. Personally, I’d much rather adhere to the system that worked for guys like Thomas Jefferson than some cloud-based shortcut.

-That being said, I don’t think the “book” part is all that important, just that it is a physical resource of some kind. If you do want a book, Moleskines are great and so are Field Notes.

-I use 4×6 ruled index cards, which Robert Greene introduced me to. I write the information on the card, and the theme/category on the top right corner. As he figured out, being able to shuffle and move the cards into different groups is crucial to getting the most out of them. Ronald Reagan actually kept quotes on a similar notecard system.

-For bigger projects, I organize the cards in these Cropper Hoppers. It’s meant for storing photos, but it handles index cards perfectly (especially when you use file dividers). Each of the books I have written gets its own hopper (and you can store papers/articles in the compartment below.

-These Vaultz Index Card boxes are also good for smaller projects (they have a lock and key as well)

-Don’t worry about organization…at least at first. I get a lot of emails from people asking me what categories I organize my notes in. Guess what? It doesn’t matter. The information I personally find is what dictates my categories. Your search will dictate your own. Focus on finding good stuff and the themes will reveal themselves.

-Some of my categories for those who are curious: Life. Death. Writing. Stoicism. Strategy. Animals. Narrative Fallacy. Books. Article Ideas. Education. Arguing with Reality. Misc.

-Don’t let it pile up. A lot of people mark down passages or fold pages of stuff they like. Then they put of doing anything with it. I’ll tell you, nothing will make your procrastinate like seeing a giant pile of books you have to go through and take notes on it. You can avoid this by not letting it pile up. Don’t go months or weeks without going through the ritual. You have to stay on top of it.

-Because mine is a physical box with literally thousands of cards, I don’t carry the whole thing with me. But if I am working on a particular section of a book, I’ll take all those cards with me. Or when I was working on my writing post for Thought Catalog, I grabbed all the “writing” cards before I hopped on a flight and through the post together while I was in the air.

-It doesn’t have to be just other people’s writing. One of my favorite parts of The Crack Up–a mostly forgotten collection of materials from F. Scott Fitzgerald published after his death–is the random phrases and observations he made. They are aphorisms without the posturing that comes with writing for publication. So many of my notecards are just things that occurred to me, notes to myself in essence. It’s your book. Use it how you want.

-Look at other people’s commonplace books. It’s like someone is separating the wheat from the chaff for you. Try a Google Books search for “Commonplace Book”–there is great stuff there.

-Use them! Look, my commonplace book is easily justified. I write and speak about things for a living. I need this resource. But so do you. You write papers, memos, emails, notes to friends, birthday cards, give advice, have conversations at dinner, console loved ones, tell someone special how you feel about them. All these are opportunities to use the wisdom you have come across and recorded–to improve what you’re doing with knowledge passed down through history.

-This is a project for a lifetime. I’ve been keeping my commonplace books in variety of forms for 6 or 7 years. But I’m just getting started.

-Protect it at all costs. As the historian Douglas Brinkley said about Ronald Reagan’s collection of notecards: “If the Reagans’ home in Palisades were burning, this would be one of the things Reagan would immediately drag out of the house. He carried them with him all over like a carpenter brings their tools. These were the tools for his trade.” I couldn’t have put it better myself.

-Start NOW. Don’t put this off until later. Don’t write me about how this is such a good idea and you wish you had the time to do it too. You do have the time. But start, now, and stop putting it off. Make it a priority. It will pay off. I promise.

If anyone wants to post photos of their Commonplace Book or describe their personal method–go for it (or email it to me). We can do a follow up post of examples and tips.

Want to follow Thought Catalog’s Commonplace Book? Find it here.

Ryan’s new book Growth Hacker Marketing, is a result of observations and notes he made from reading and interviewing a new class of thinkers who disrupted the marketing industry. Or check out his other articles here.