A full version of this article was first published on CriticalMargins.com.

For centuries, authors and thinkers have kept commonplace books: focused journals that serve to collect thoughts, quotes, moments of introspection, transcribed passages from reading — anything of purpose worth reviewing later.

Why keep a commonplace book today? When we are inundated by information through social media and our digital devices, it’s easy to overlook what drives and intrigues us. Keeping a journal helps, but keeping a focused journal is better, even if that focus is on self-fulfillment.

A commonplace book helps you process, understand, and retain anything that’s valuable to you. Ryan Holiday, in his article “How and Why to Keep a Commonplace Book,”  for Thought Catalog, defines a commonplace book as “a central resource or depository for ideas, quotes, anecdotes, observations and information you come across during your life and didactic pursuits.” In other words, a “thinker’s journal.”

Writers like Virginia Woolf and Samuel Johnson kept commonplace books, and the practice is alive and well today. Do a quick Google search of “commonplace book” and you’ll find examples of how people use their commonplace books on paper and on apps like Evernote.

Woolf wrote about the practice in her essay “Hours in a Library”:

Let us take down one of those old notebooks which we have all, at one time or another, had a passion for beginning. . . . Here we have written down the names of great writers in their order of merit; here we have copied out fine passages from the classics; here are lists of books to be read; and here, most interesting of all, lists of books that have actually been read, as the reader testifies with some youthful vanity by a dash of red ink. (Virginia Woolf, “Hours in a Library”)

What else can a commonplace do for you compared to keeping other types of journals? I’ve kept a commonplace book for a few years now and it’s become a routine. Here’s what I’ve gained from the practice.

Helps keep me mentally flexible

When I read, I keep in mind the things that interest me most or that I think will benefit me long term. I mark these things and then add them to my commonplace book. I try to do this daily or weekly. As a result, my reading practice has changed: I read in part to find things that can keep me mentally flexible. By that I mean I purposely seek out contrary ideas or things I don’t know already or want to understand better. The best of what I discover goes into my commonplace book. Over time, what I’ve collected begins to tell a story about how I view the world and how I understand things I don’t agree with or won’t need to know later.

Allows for reflection without rumination

With an open-ended journaling practice like the morning pages method, it becomes too easy to fall into patterns of self-doubt and rumination. You can lose focus on your goals if you spend too much time on things you can’t control. A commonplace book can keep you focused. Self-reflection only works if you use it to learn and adapt, and rumination rarely leads to positive outcomes.

I find I can fight against self-doubt or avoid navel-gazing by focusing on what I’ve acquired: a meaningful song lyric, a poignant sentence from an essay, a funny tweet. The whole of these acquired ideas becomes its own narrative, and one worth keeping for later.

Builds the framework for a mind palace

Cognitive scientists say creative thinking can come from connecting disparate ideas that wouldn’t otherwise cross paths. I’m always looking for things to add to my commonplace book, and this leads to new connections and creative breakthroughs. The quote from a science fiction novel I’m reading sits next to a pasta recipe I found online, which leads to a new plot line in the short story I’ve been writing for months. Who knew?

Do what works for you

I’ve discovered things about myself through my commonplace book. It’s led me to read things I wouldn’t have read before. I make new connections between ideas that would have not connected in my mind without this focused exercise.

I write on paper because I like to see my progress: I keep my notebooks lined on my bookshelf and read through them every now and then. I also keep a digital commonplace book on Evernote, but I find the best stuff goes into my notebook. Writing it out helps me remember it better.

But you can do what works for you, and that’s the beauty of keeping a commonplace book. With some basic organizational methods, your commonplace can become useful later.

About the Author

Kevin Eagan is a book editor who lives in Central Florida. He writes about reading and writing in the digital age on his blog CriticalMargins.com. You can see what he's up to at his website KevinThomasEagan.com.