Book Summary: Expand your memory. Boost your thinking.

Building a Second Brain: A Proven Method to Organize Your Digital Life and Unlock Your Creative Potential

by Tiago Forte

Every day we face a flood of information. Some of it is useful. Much of it not. Some of us try to hoard as much as we can. Others let the bulk of it slide because they don’t have good filters for what’s useful or they’re too overwhelmed to deal with it. But, embedded in what’s slipping by are bits of information—gems—that could be invaluable for improving our relationships, advancing our careers, or developing our organizations.

The hoarders don’t fare better. Much of what they collect (warehouse) molders out of sight and certainly out of mind. In both cases, the gems are out of reach of the only place they could be useful, our attention. What if we could harness the power of technology to deal with the onslaught, capture the useful stuff, put it to work or organize it for future use, and ultimately benefit from the wealth of information we face every day? That’s the question this book answers.

At its core, Building a Second Brain is about capturing, organizing, developing, and using knowledge–much of it gleaned from the information you encounter every day and the reading and work that you’re already doing. On another level, it’s about rethinking “knowledge” and our work. Viewing our work products as “knowledge assets” rather than as undifferentiated masses of “stuff.” Recognizing that these assets already have value but can be enhanced or combined to make them even more valuable. As assets, it’d be wise of us to keep track of, steward, and develop them.

In the author’s words: “To be able to make use of information we value, we need a way to package it up and send it through time to our future self. In the same way that personal computers changed how we interact with technology, knowledge management can help us harness the full potential of what we know. [A Second Brain] is a digital archive of your most valuable memories, ideas, and knowledge to help you do your job, run your business, and manage your life without having to keep every detail in your head.”

This summary reflects my takeaways from a useful book I recommend to others. Reading a summary isn’t a substitute for reading the book. There’s much more than I can cover here. Plus, this is my interpretation. If these ideas resonate with you, I encourage you to get a copy from your favorite bookseller. Here are the Amazon links: e-book | Audiobook | Print

Unless otherwise noted, all quotes should be attributed to the book’s author.


What is a Second Brain?

“Second Brain” is Forte’s approach to what is generically called a “personal knowledge management system” or “PKM.” A PKM system is a set of tools and practices that you can use to capture, organize, develop, and share information and knowledge. It is both an archive and a thinking space that can help you stay organized and on top of your work, improve your productivity, and enhance your professional and personal development. (For simplicity’s sake, I’ve used the term “second brain” throughout, regardless if it applies to PKM generically or Forte’s take on it. –DT)

Various tools can support a Second Brain, including paper files and notebooks, digital tools such as personal information managers, note-taking and outlining apps, cloud-based storage, whiteboards, and collaboration platforms. For most, a physical notebook or note-taking app is the hub of their system, and that’s the approach this book takes.

For centuries, artists, intellectuals, and academics have used commonplace books to organize their thinking, envision new creations, and reflect on the world. A file of papers or a blank notebook, the commonplace book gained popularity during the Industrial Revolution as advances in printing, transportation, and communication began the explosion of information that continues today.

We can draw on this historical practice, updated with today’s tools and technology, to manage the wealth of information available to us–to tame the flood and turn it to our advantage.

What a Second Brain system can do:

  • Find important information within seconds.
  • Help advance our projects and goals more consistently because of organized knowledge.
  • Save our best thinking for future projects.
  • Help us connect ideas and notice patterns.
  • Share our work and collaborate more efficiently.
  • Keep track of details so we can turn work off.
  • Help us spend less time looking for things and more time creating.

How people use their Second Brain system: Forte observes that people go through a natural progression of stages in adopting a Second Brain system:

  1. To remember. Rather than attempting to recall facts and ideas, they save them.
  2. To connect. Initially a memory tool, their Second Brain becomes a thinking tool where ideas get honed and developed into something more valuable.
  3. To create and share. The more concrete their knowledge of a subject becomes, the more confident they become in sharing their ideas and positively influencing others.

Your Second Brain is always on, has perfect memory, and can scale to any size. The more you outsource and delegate the jobs of capturing, organizing, and distilling to technology, the more time and energy you’ll have available for the self-expression that only you can do.

How a Second Brain works

  1. Make your ideas concrete. It’s a tool where you can offload your ideas so you can think clearly about them and start implementing them. Digital notes transform thoughts and abstract ideas into tangible things we can arrange, edit, and combine.
  2. Reveal new associations between ideas. Creativity is about connecting ideas. Keeping notes from different sources together in one location makes it easier to notice unusual associations–facilitating connectivity.
  3. Incubate your ideas. When we take on a project, a Second Brain can provide weeks, months, or years of accumulated wisdom and examples to draw on.
  4. Sharpen your unique perspective. Beyond organizing other people’s ideas, a Second Brain can help facilitate your thinking as you develop and express your own ideas. It can provide a deep well of inspiration.

Notes are the common currency of any PKM system

A note is simply a piece of information. It can be a standalone bit of knowledge, but it could also be a part of something larger, such as a new design, a proposal, a story, a report, a book, or a smaller work product. These aren’t the disposable notes we took in school. Instead, they’re knowledge assets–the building blocks of knowledge in our Second Brain. Some examples:

Reading highlights
Links to interesting content
Voice memos
Meeting notes
Photos and other images
Takeaways from courses, conferences, or presentations
Stories and favorite anecdotes
Insights and realizations
Memories and experiences you don’t want to forget
Reflections, thoughts and lessons
Musings and random ideas

Notes: Paper or digital?

Paper and most note-taking apps share these four characteristics:

  • Multimedia. You can store a wide variety of content, including text, images, audio, or video.
  • Accessible. Make it easy to capture thoughts as soon as they occur to you.
  • Open-ended. Notes allow for free-form exploration of ideas, even before you have a clear goal.
  • Action-oriented. Allow for quick capture of your stray thoughts so you can remain focused.

But digital notes enable you to search, share, backup, edit, link, and sync between devices.

The benefits of externalizing your thoughts

Remember better. When you write something down in your own words, you are more likely to remember it because of the “generation effect.” Research has found that when someone speaks or writes a series of words, more parts of their brain are activated than when they read them.

Greater objectivity. A first encounter with an idea may not be the best time to determine its meaning. You’ll gain objectivity by setting it aside to return to later. With a Second Brain, ideas do not have to be acted upon immediately, or they will be lost. And, once they’re outside our heads, we can examine our thoughts more objectively–play with them, and improve them.

Generate compound interest from your thoughts. Knowledge isn’t just textbook excerpts. In the digital age, knowledge is often embedded in “content”–external and self-created content. These knowledge assets can be anything that helps solve a problem, save time, clarify a concept, or learn from experiences. Songwriters compile hook books, software engineers build code libraries, lawyers keep case files, and marketers maintain “swipe files” of examples.

Your Second Brain is like a mind cathedral that you can step into any time you want to shut out the world and imagine a world of your own.

The CODE method for navigating your information world

The CODE method–Capture, Organize, Distill, and Express–is Forte’s framework for navigating and making sense of your world of information.

CAPTURE what resonates

Capture only the ideas and insights that you think are truly noteworthy. Make intentional decisions about what you need to keep. Keep only what resonates in a trusted place you control, and leave the rest aside.

Use your intuition to see what inspires you: a sense of pleasure, curiosity, wonder, or excitement. Ideas that strike a chord are often unconventional, counterintuitive, intriguing, or potentially useful. A sense of resonance is your intuition telling you something is “notable;” why doesn’t matter.

Capture 10 percent or less. More than 10 percent of the source means you’ll have trouble wading through all the material in the future. This also is the highlight exporting limit imposed by most e-book publishers.

The more rigorous you are now, the less you’ll have to wade through later. A brief note should contain only the most salient, relevant, and rich material. Adopting a curator’s perspective can help, which means taking charge of the information you gather.

Questions to help you decide what’s worth keeping:

  1. Is it useful? Maybe not now, but in the future?
  2. Does it inspire you? A collection of inspiring quotes, photos, ideas, and stories can shift your perspective and provide motivation and inspiration.
  3. Is it personal? Does it reflect your unique perspective?
  4. Is it surprising? If not, you probably already know this. Is there any other reason to keep it?
  5. Does it support or contradict? The key to learning is to take in information from different sources rather than jump to conclusions when we encounter ideas that conflict.
  6. Does it help organize? In your notes, chapter titles, headings, and lists can add structure based on work already done by the author.

Feynman’s twelve favorite problems approach: Nobel prize-winning physicist Richard Feynman’s approach to filtering the information most important to him was maintaining a list of open questions. “You have to keep a dozen of your favorite problems constantly present in your mind,” Feynman told one interviewer. “Every time you hear or read a new trick or a new result, test it against each of your twelve problems to see whether it helps.”

Knowledge capture is about mining the richness of the reading you’re already doing and the life you’re already living.

ORGANIZE for actionability

Your Second Brain isn’t just a tool—it’s an environment. Once you’ve created this environment, you’ll turn to it when it’s time to execute or create. You’ll have a dedicated space with materials organized to support your thinking and action.

Organize your notes based on how you intend to use them. Rather than organizing them around the source or topic, organize them around what the ideas or information can do—what they can help you achieve. Begin with the projects you are currently working on. Ask, “How will this help me advance one of my current projects?”

Organizing for action gives you clarity because everything you keep has a purpose. It simplifies the vast amount of information out there. Only some things are actionable and relevant; you can ignore everything else.

Use “PARA” (Projects, Areas, Resources, Archives) to organize your information.

Every piece of information you save can be classified into one of four categories using the PARA system:

  • Projects are the short-term efforts you’re working on now that have a clear timeline and desired outcome. Because of this, the information filed here is the most actionable.
  • Areas of responsibility are long-term commitments you must manage over time. While there’s no goal to strive for, there are standards to meet. The longer time horizons mean these items are actionable in the future.
  • Resources are topics or interests that may be useful in the future. This includes any topic you’re researching that doesn’t belong to a project or an area.
  • Archives contain inactive items from the other three categories that are kept in long-term storage until they are needed again.

You can use PARA to organize all your files, not just your note-taking app, but your digital files and anywhere else you keep your information. When organizing, whether it’s PARA or your version, it’s helpful to use a naming system based on actionability. When you standardize your organizing system, you’ll always know where to find the information you need.

The world of work is one of action and deadlines. Our filing system should reflect that. We tend to organize and file by topic because school was organized by topics.

Separate the capturing and organizing activities. The worst time to “file” an idea is when it’s fresh, and you haven’t given it enough thought. In addition, keeping what resonates during the capture stage differs from deciding where to store something for the future.

Completed projects are the PKM’s oxygen. They keep the system nourished and fresh and keep you motivated. Concrete wins lead to a sense of “determination, momentum, and accomplishment.”

Note taking is like time travel—you are sending packets of knowledge through time to your future self.

DISTILL to highlight the essence

Distilling collected ideas will increase their value and improve their discoverability later.

Every idea has an “essence,” which is the core of what it wants to say. Regardless of the length, there is always a way to get the main point across in just a sentence or two. When you take a note, ask yourself, “How can I make it useful for my future self?” That question will guide you toward the words and phrases that explain why you saved it, what you thought, and what caught your attention.

Think of yourself as a note-giver. You’re giving your future self the gift of easily accessible knowledge. As a note giver, your job is to preserve the notes you’re taking so they survive the journey into the future.

Discoverability = future value

The future value of your notes depends on how easily you can find what they contain and access the most valuable points. Discoverability refers to “the degree to which a piece of content or information can be found in a search of a file, database, or another information system.” Highlighting key points can help your notes stand out, along with tagging, linking, and descriptive titles.

Use “progressive summarization” to distill ideas. “Progressive Summarization” is Forte’s method for reducing notes to their key points. The method is simple: highlight a note’s main points, then highlight those highlights, and so on, distilling a note’s essence in several “layers.” Each layer is formatted differently to distinguish them.

  • The first layer is the item you initially saved in your notes–a thought or an excerpt from a source.
  • The second layer is bolding the main points, keywords, and phrases that resonate.
  • The third layer is highlighting the essential bits from the second layer. Reserved for long, interesting, or especially valuable notes,
  • The fourth layer, only for especially important notes, is adding an “executive summary” at the top with a few bullet points that summarize the note in your own words.

Each layer of highlighting should include only 10–20% of the previous layer. If your note has 500 words, the second layer (bolded) should have 100 words or fewer, and the third layer (highlighted) should have up to 20 words.

Three common distilling mistakes:

  1. Over-highlighting. If you’re going to capture everything, you might as well capture nothing. You shouldn’t include every tiny detail.
  2. Highlighting without a purpose in mind. The rule of thumb to follow is that every time you “touch” a note, make it a little more discoverable for your future self by adding a highlight, a heading, bullets, or commentary.
  3. Making highlighting difficult. Trust your intuition to figure out if a passage is relevant. It’s unnecessary to analyze, interpret, or categorize each point to decide whether to highlight it. If it’s too much work, you’ll lose focus.

For the note’s contents, listen for a feeling of internal resonance, as you did when saving the content.

Imagine your future self as a demanding customer. They will surely be impatient and swamped. They won’t have time to pore through page after page of details to find the hidden gems. It’s your job to “sell” them on the value of the notes you are taking now.

EXPRESS to show your work

Think in terms of intermediate packets. Express is about sharing what you know and starting that sharing process before everything is perfect. Using intermediate packets, you can test what works and gather feedback by sharing your ideas earlier, more frequently, and in smaller chunks.

Intermediate packets are building blocks. These are intermediate steps on the way to a finished product. For example, testing book chapter ideas by posting articles (intermediate packets) and getting feedback. Intermediate packets can also include things that you develop or “recycle,” such as:

  1. Distilled notes from books or articles you’ve read.
  2. Material not used in past projects that could be used in future ones.
  3. Work-in-progress and deliverables from previous projects.
  4. Documents made by someone else in or around your organization.

Intermediate packets can enhance our creative process:

  1. Focusing on one small packet at a time is a great attention management tool and makes us less prone to the ill effects of interruptions.
  2. You can make progress anytime. Instead of waiting for blocks of uninterrupted hours, you can fit smaller packets into smaller time blocks.
  3. Smaller pieces are easier to share for both collaboration and soliciting feedback.
  4. As the number of intermediate packets grows, you can start completing projects simply by assembling them.

Intermediate packets reframe creative work from an all-consuming endeavor to an ongoing cycle of creating and delivering value in small, doable chunks. They also reframe productivity. Instead of thinking of your job as tasks that require you to be there and do everything yourself, think of it as creating knowledge assets and building blocks.

Retrieval. Information can be retrieved in four ways that overlap and complement each other: search, browsing, tags, and serendipity.

Visual patterns amplify serendipity. It’s valuable to save images, not just text. Intuitively, we perceive visuals in a blink of an eye–much faster and with far less energy than reading.

Creative execution is a process

Our ability to come up with brilliant ideas on demand isn’t guaranteed. Innovation and problem-solving depend on routines that continually bring new ideas to our attention.

Divergence and convergence are the heart of the creative process

Divergence is expansive–it is finding and generating new ideas or solutions. It’s spontaneous, chaotic, and messy. Let your mind wander.

During convergence, we narrow down and focus on what’s significant. We eliminate options, make trade-offs, and determine what is essential.

Divergence and convergence repeat throughout the creative process. Once you finish one cycle of convergence, you can apply what you’ve learned to a new cycle of divergence. Iterate back and forth until your project or intermediate packet is complete.

Divergence and convergence are built into the CODE method:

  • Capture and Organize are divergent. They involve taking a wide view to gather information and make connections and associations.
  • Distill and Express are convergent. They are about narrowing down, developing, and building something from the materials you have at hand.

Convergence can be challenging, so it’s tempting to revert to divergence—to do more research. This diversion may feel productive and forward-looking, but it also delays completion.

Ideas to support creative work

  1. Organize notes like stepping stones to aid completion. It’s a twist on outlining that separates the tasks your brain struggles with most: selecting ideas and organizing them logically.
  2. Use a Hemingway Bridge to maintain momentum. Hemingway stopped writing when he knew the next plot point in the story so he’d know where to begin the next time he sat down to write. Instead of burning out your ideas and energy, stop when your session time is up. Then spend a few minutes writing down the next steps for your project.
  3. When you’re stuck, dial down the scope to something more doable. Scaling back the product or deferring the least important parts helps you unblock and move forward.

The only way to know whether you’re getting the good stuff is to try putting it to use in real life.

When you begin expressing your ideas and turning your knowledge into action, life begins to change.

The three habits most important to your Second Brain

  1. Use project checklists to start and finish projects consistently and leverage previous work.
  2. Conduct weekly and monthly reviews to take stock of your work and life and decide if anything needs to be changed.
  3. Hone your “noticing habits” to identify what to edit, highlight, or move notes for future reference.

Think like an investor

To accelerate the knowledge-compounding effect, treat your attention as an asset that produces a return that can be reinvested, creating more substantial, better assets. The profits of your attention will compound as your knowledge assets grow as your ideas connect and build on each other.

When you transform your relationship to information, you will begin to see the technology in your life not just as a storage medium but as a tool for thinking. Like a bicycle for the mind, once we learn how to use it properly, technology can enhance our cognitive abilities and accelerate us toward our goals far faster than we could ever achieve on our own.

Book details and where to buy it:

Get the book on Amazon: e-book | Audiobook | Print (affiliate links*)

Amazon rating: 4.6 of 5 stars

Goodreads rating: 4.2 of 5 stars

Page count: 269

Publication date: June 14, 2022

Author website:

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