This is a summary of Building a Second Brain, my online course on capturing, organizing, and sharing your knowledge using digital notes.

How many brilliant ideas have you had and forgotten? How many insights have you failed to take action on? How much useful advice have you slowly forgotten as the years have passed?

We feel a constant pressure to be learning, improving ourselves, and making progress. We spend countless hours every year reading, listening, and watching informational content. And yet, where has all that valuable knowledge gone? Where is it when we need it? Our brain can only store a few thoughts at any one time. Our brain is for having ideas, not storing them.

Building a Second Brain is a methodology for saving and systematically reminding us of the ideas, inspirations, insights, and connections we’ve gained through our experience. It expands our memory and our intellect using the modern tools of technology and networks.

This methodology is not only for preserving those ideas, but turning them into reality. It provides a clear, actionable path to creating a “second brain” – an external, centralized, digital repository for the things you learn and the resources from which they come.

Being effective in the world today requires managing many different kinds of information – emails, text messages, messaging apps, online articles, books, podcasts, webinars, memos, and many others. All of these kinds of content have value, but trying to remember all of it is overwhelming and impractical. By consolidating ideas from these sources, you’ll develop a valuable body of work to advance your projects and goals. You’ll have an ongoing record of personal discoveries, lessons learned, and actionable insights for any situation.

We are already doing most of the work required to consume this content. We spend a significant portion of our careers creating snippets of text, outlines, photos, videos, sketches, diagrams, webpages, notes, or documents. Yet without a little extra care to preserve these valuable resources, our precious knowledge remains siloed and scattered across dozens of different locations. We fail to build a collection of knowledge that both appreciates in value and can be reused again and again.

By offloading our thinking onto a “second brain,” we free our biological brain to imagine, create, and simply be present. We can move through life confident that we will remember everything that matters, instead of floundering through our days struggling to keep track of every detail.

Your second brain will serve as an extension of your mind, not only protecting you from the ravages of forgetfulness but also amplifying your efforts as you take on creative challenges.

The Building a Second Brain methodology will teach you how to:

  1. Consistently move your projects and goals to completion by organizing and accessing your knowledge in a results-oriented way
  2. Transform your personal knowledge into income, taking advantage of a rapidly growing knowledge economy
  3. Uncover unexpected patterns and connections between ideas
  4. Reduce stress and “information overload” by expertly curating and managing your personal information stream
  5. Develop valuable expertise, specialized knowledge, and the skills to deploy it in a new job, career, or business
  6. Cultivate a collection of valuable knowledge and insights over time without having to follow rigid, time-consuming rules
  7. Unlock the full value of the wealth of learning resources all around you, such as online courses, webinars, books, articles, forums, and podcasts

Part I: Remember

The first step in building a second brain is “capturing” the ideas and insights you think are worth saving. Ask yourself:

  • What are the recurring themes and questions that I always seem to return to in my work and life?
  • What insightful, high-value, impactful information do I already have access to that could be valuable?
  • Which knowledge do I want to interconnect, mix and match, and periodically resurface to stimulate future thinking on these subjects?

Most of the time we tend to capture information haphazardly – we email ourselves a quick note, brainstorm some ideas in a Word document, or take notes on books we read – but then don’t do anything with it. We are already consuming or producing this information, we just need to keep it in a single, centralized place, such as a digital note-taking app like Evernote, Microsoft OneNote, Bear, Notion, or others. These apps facilitate capturing small “snippets” of text, and can also store hyperlinks, images, webpages, screenshots, PDFs, and other attachments, all of which are saved permanently and synced across all your devices.

By keeping a diverse collection of information in one centralized place, it is free to intermix and intermingle, helping us see unexpected connections and patterns in our thinking. This also gives us one place to look when we need creative raw material, supporting research, or a shot of inspiration.

The following three guidelines will help you capture only the most relevant and useful information in your second brain

A) Think like a curator

It is tempting to turn on our mobile device or computer and immediately become immersed in the flow of juicy information we are presented with. Much of this information is useful and interesting – articles written by experts that could make us more productive, tips on exercise or nutrition, or fascinating stories from around the world. But unless we make conscious, strategic decisions about what we consume, we’ll always be at the mercy of what others want us to see.

Instead, adopt the mindset of a curator – objective, opinionated, and reflective. As you come across social media updates, online articles, and podcasts throughout your day, instead of diving in immediately, save them for future consideration. As you begin to collect content, you’ll be able to choose which sources to consume in a deliberate way.

B) Organize your content by project

How should you organize the content once you’ve captured it? Instead of organizing your files primarily by topic (for example, web design or psychology), which is time-consuming and mentally taxing, organize them according to the projects you are actively working on. This ensures that you are consuming information with a purpose – to advance your projects and goals – and only at a time and place where you’ll be able to put it to use.

The PARA organizational system takes this principle – organizing information by when you would like to see it next – and applies it to your entire digital life. Instead of organizing each one of the information management tools you use in a completely different way, use your projects as universal categories across all of them. This helps reduce the fragmentation of your project files, without requiring you to only use one tool for everything.

C) Keep only what resonates

The word “organization” often brings to mind an analytical way of thinking. But analysis is time-consuming and tiring. In deciding which passages, images, theories, or quotes to keep, don’t make it a highly intellectual, analytical decision.

Instead, your rule of thumb should be to save anything that “resonates” with you on an intuitive level. This is often because it connects to something you care about, wonder about, or find inherently intriguing. By training ourselves to notice when something resonates with us at a deeper level, we improve not only our ability to see opportunities, but also our understanding of ourselves and how we work.


Part II: Connect

Once you start collecting valuable knowledge in a centralized place, you’ll naturally start to notice patterns and connections. An article you read on gardening will give you an insight into online marketing. An offhand comment by a client will give you the idea of creating a webpage with client testimonials. A business card you saved from a conference will remind you to follow up and propose a collaboration.

You can greatly facilitate and speed up this process by distilling your notes into actionable, bite-sized summaries. It would be near impossible to review your 10 pages of notes on a book you read last year in the midst of a chaotic workday., for example. But if you had just the main points of that book in a 3-point summary, you could quickly remind yourself of what it contains and potentially apply it to something you’re working on

The following three guidelines will help you summarize and distill your notes into actionable, useful tools for execution.

A) Design notes for your future self

A powerful mindset for interacting with our notes is to “design notes with your future self in mind.” Every time we create a note or make an edit, we can make it just a little easier to find and make use of next time.

This can include:

  • Defining key terms in parentheses in case we forget what they mean
  • Inserting placeholders when we leave off summarizing a source so we know where to pick back up
  • Adding links to related websites, files, or emails that we’re likely to forget over time

By constantly saving packets of knowledge in a format that our future self can easily consume, we follow a “pay it forward” strategy that we get to benefit from in the future!

B) Summarize progressively, at different levels of detail

A common problem with notes is that they are too long and dense. You can’t afford the time it would take to review and remind yourself of everything they contain. Executive summaries can help, but often it is a challenge to identify what exactly the main point is in the first place.

Progressive Summarization is a technique that relies on summarizing a note in multiple stages over time. You save only the best excerpts from whatever you’re reading, and then create a summary of those excerpts, and then a summary of that summary, distilling the essence of the content at each stage. These “layers” are like a digital map that can be zoomed in or out to any level of detail you need. Progressive Summarization allows you to read the note in different ways for different purposes: in depth if you want to glean every detail, or at a high level if you just need the main takeaway. This allows you to review a note’s contents in seconds to decide if it’s useful for the task at hand.

C) Organize opportunistically, a little bit at a time

It can be tempting to spend a lot of time to create highly structured, perfectionistic notes. The problem is, you often have no idea which sources will end up being valuable until much later. Instead of investing a lot of effort upfront, organize your notes opportunistically, in small bits over time

Your rule of thumb should be: add value to a note every time you touch it. This could include adding an informative title the first time you come across a note, highlighting the most important points the next time you see it, and adding a link to a related note sometime later. By spreading out the heavy work of organizing your notes over time, you not only save time and effort, but ensure that the most frequently used (and thus most valuable) notes surface organically, like a ski slope where the most popular routes naturally end up with deeper grooves.

Part III: Create

All of this capturing, summarizing, connecting, and organizing has one ultimate purpose: creating tangible results in the real world. Whether we want to lose weight, get a promotion at work, start a side business, or contribute to a cause we believe in, the true purpose of learning is to turn our knowledge into effective action.

With a substantial reserve of supporting material in your second brain, you never need to sit down to an empty page and try to “think of something smart.” All creativity stands on the shoulders of giants, and you have the benefit of already having the best ideas of those giants documented in your notes!

What should you create? It depends on your skills, interests, and personality. If you are analytical, you could draw on a group of articles you’ve read about Big Data to write a blog post summarizing where you think machine learning is headed next. If you like to perform, you could borrow ideas from your notes on YouTube cooking videos you’ve enjoyed to make one of your own. If you are campaigning for investment in your local park, you could distill the minutes from past city council meetings into a speaking agenda for your public comments at the next one.

With a second brain at your disposal, you always have something to inspire you, remind you, support you, or guide you as you engage in the projects and interests that are important to you. You are able to draw on the sum total of your life experience and learning, not just whatever you can think of in the moment.

The following three guidelines will help you create more, better, and more meaningful creative output for whatever purpose you decide is important.

A) Don’t just consume information passively – put it to use

A common challenge for people who love to learn is that they constantly force-feed themselves more and more information, but never actually put it to use. The goals and the experiences that would enrich their lives get endlessly postponed, waiting for the “right” bit of knowledge they supposedly need before getting started.

But information only becomes knowledge – something personal, embodied, grounded – when we put it to use. That’s why we should shift as much of our effort as possible from consuming information, to creating new things. The things we create – whether they are writing pieces, websites, photographs, videos, or live performances – embody and express the knowledge we’ve gained from personal experience. We all need to be part of bringing to life something good, true, or beautiful. Creating things is not only deeply fulfilling, it can also bring us unexpected opportunities, introduce us to new friends or collaborators, and have a positive impact on others – by inspiring them, entertaining them, or informing them.

B) Create smaller, reusable units of work

Once you start to curate a collection of valuable knowledge in external form, a very different way of working becomes not only possible, but necessary.

You will begin to think of your projects as made up of discrete parts. I call them “intermediate packets,” which can include any kind of content we’ve already mentioned: a set of notes from a team meeting, a list of relevant research findings, a brainstorm with collaborators, a slide deck analyzing the market, or a list of action items from a conference call, for example.

Instead of trying to sit down and move the entire project forward all at once, which is like trying to roll a giant boulder uphill, a more effective approach is to end each work session – whether it is 15 minutes or 3 hours – by completing just one intermediate packet. This allows you to work in smaller increments, making use of any available span of time, while getting lots of feedback and taking frequent breaks. Not only does this result in higher quality output, it fuels the motivation and the inspiration that we need to do our best work. These packets can then be saved to your second brain, and re-used the next time you have a similar need.

C) Share your work with the world

There are many benefits all along the process of building a second brain: less stress, better focus, more insights, and enhanced productivity. But the real payoff comes at the end, when you create something out of the knowledge you’ve collected and share it with the world.

It can be tempting to wait until everything is “ready,” until you have all the information you think you need, and all the sources have been double-checked and reviewed. But as you continually curate and save pieces of content, review and summarize them, create a series of intermediate packets, and then recycle them back into your second brain, you’ll start to realize that there is no such thing as a finished product.

Everything is in flux, everything is a work in progress, and everything you put out there has an implicit “version 1.0” attached to it. This can be tremendously empowering – since nothing is ever final, there is no need to wait to get started. You can publish a simple website now, and slowly add additional pages as you have time. You can publish a draft blog post now, and make revisions later after you’ve received feedback. You could even self-publish an ebook on the Kindle store, and any future updates to the manuscript will be wirelessly synced to everyone who purchased the book!

By consistently sharing your work with others – whether that is your family, friends, colleagues, or externally on social media – all sorts of benefits will start to materialize. You’ll connect with new collaborators who you never would have imagined would find your work compelling. You’ll find clients or customers, in some cases even when you weren’t seeking them. Others will reflect back to you their reactions and comments and appreciation (and occasionally criticism). You’ll find that you are part of a community that shares your interests and values. Accomplishing anything meaningful or important requires working with others, and the incredible power of the internet now allows us to find each other no matter how obscure or strange our interests.


Each note in your second brain is a record of something you’ve experienced in your life – whether that is from reading a book, having an interesting conversation, or completing a project at work. With all your most valuable ideas at your fingertips at all times, you never need to struggle and strain to remember everything you’ve learned.

As your Second Brain gains momentum over weeks and months, you will start to become different. You will no longer think about things in isolation, but as part of a network of ideas in which everything affects everything else. You’ll realize that something you learned at work about effective communication also applies to your family vacation debate.. A random fact you read in an airplane magazine will somehow end up being useful in a blog post you’re writing. A lesson from Ancient Greek history you picked up from a podcast on your morning commute will help you deal with a crisis at the office. You will start to think in terms of the systems and principles that you’ve gleaned through your summarizing and reviewing, and see them everywhere.

Your mind will start to work differently, learning to depend on this external tool to draw on resources, references, and research far beyond what it can remember on its own. You will start to conceive of “your work” as an integrated whole that you can actually point to, shape, and navigate in a direction of your choosing. You’ll be more objective and unattached, because if any single idea doesn’t work out, you know you have a huge trove of others ready to go.

Over time, you will start to recognize that everything you are learning and experiencing makes sense. You can see, mapped in the notes you are cultivating, the underlying structure of your life. Why you do things, what you really want, what’s really important and what isn’t. Your second brain becomes like a mirror, reflecting back to you who you think you are, who you want to be, and who you could become. Because you know how to capture and make use of anything, every experience you have becomes an opportunity to learn and to grow.

As this self-understanding dawns, you will look around at the notes you’ve collected, and you will realize that you already have everything you need to get started. You will start combining the ideas together, forming new perspectives, new theories, and new strategies. Ideas about society, about art, about psychology, about spirituality, about technology will start intermixing and spawning ideas you’ve never consciously considered. You’ll be shocked, in fact, at the elegance and power of what pops out of your notes.

This epiphany won’t just exist in your head. People can tell. They’ll start to notice that you can draw on an unusually large body of knowledge at a moment’s notice. They will admire your amazing memory, but what they don’t know is that you never try to remember anything. They’ll admire your incredible self-discipline and dedication at developing ideas over time, not knowing that you’ve created a system in which insights and connections emerge organically. They’ll be impressed by your ability to produce so much creative output, but in reality, you never lock yourself in a room to “crank out” some work. You just let your projects simmer until they’re ready.

Building a Second Brain is an integrated set of behaviors for turning incoming information into completed creative projects. Instead of endlessly optimizing yourself, trying to become a productivity machine that never deviates from the plan, it has you optimize an external system that is more reliable than you will ever be. This frees you to imagine, to wonder, to wander toward whatever makes you come alive here and now in the moment.

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