Building a Second Brain - Summary, Notes and Highlights

Building a Second Brain - Summary, Notes and Highlights

by | 9 min read

What if all the time spent reading was not wasted. In building a second brain you learn how to organise your notes so you can unlock your creative potential.

These are my notes and highlights from the book Building a Second Brain by Tiago Forte.

🌳 How This Book Changed My Life

I have a shelf full of self-help and entrepreneurship books, many of which I have read and others which I have still to read.

Do you know what the big difference is between the unread and the read?


There are very few books I have read that I could tell you in enough detail what it was about and the lessons I have learnt from it.

After looking into note-taking and the Zettelkasten method, I discovered Tiago Forte’s blog and learned about his upcoming book Building a Second Brain (Tiago Forte).

I now have a process I go through to take highlights while I am reading and then form these into book notes (like the one you are reading now).

🤔 What Is This Book About?

This book shows you how to organise your knowledge in a way that is discoverable and actionable when you need it.

Building a second brain allows you to get all of your ideas and knowledge out of your head, giving you space to be more creative.

If you are interested in the topic in general, it is worth searching for Zettelkasten or Digital Garden.

👤 Who Should Read It?

Anyone who is involved with knowledge work, which covers most jobs these days.

If you are tired of reading books, articles and watching videos but never remembering anything or being able to use it in the future, you need to read this book.

For example, if you are learning to code, wouldn’t it be great to have all your notes in one place where you could easily refer to them when you required them.

📒 Summary & Notes

In the past, writers and creatives used to keep “commonplace books” to store all of their thoughts and inspiration. This is especially helpful for writers who never know when inspiration might strike.

Typically, this would be a small notebook and pen that they could keep on themselves throughout the day and write down anything that comes to mind, so they don’t forget it.

There are now quite a few methods people have come up with for storing digital notes. There is the Zettelkasten/Slipbox method, original used by Niklas Lehmann. He used cards in a box to keep all of his notes in and would number them all as a reference so that each card could make reference to other cards.

The main point is our brains are not meant for storing information, they are meant for connecting thoughts. If you spend all your time trying to remember things, your brain has less capacity to come up with interesting thoughts and connections.

This is where your second brain comes in. It is a place where you can store all your ideas and knowledge so that you can easily call upon it when you need it.

There are quite a few options for your second brain. The main ones are Notion, Obsidian and Roam.

Benefits of keeping a second brain

Tiago outlines a few key benefits you get from keeping a second brain:

  1. Making our ideas concrete.
  2. Revealing new associations between ideas.
  3. Incubating our ideas over time.
  4. Sharpening our unique perspectives.

You need to “feed” your second brain with ideas and thoughts for it to be useful. You don’t get an immediate benefit until you have invested some time into putting your ideas on to “paper”.

There is even significant evidence that expressing our thoughts in writing can lead to benefits for our health and well-being.” One of the most cited psychology papers of the 1990s found that “translating emotional events into words leads to profound social, psychological, and neural changes.”

So, how do you actually “feed” your second brain and what information do you store in it?

What to store in your Second Brain?

When people first start trying to keep notes, they have a tendency to just want to save everything. You might read an interesting article, for example and decide to save the whole text in your notes.

This defeats the purpose of a second brain. The aim is to store your insights and ideas from what you are reading. These can then be interspersed with highlights from the article or book if you wish.

The book outlines a 4-step process for storing your notes:

  1. Capture - Keep What Resonates
  2. Organise - Save For Actionability
  3. Distill - Find The Essence
  4. Express - Show Your Work

As a software developer, I particularly like that this has the acronym CODE.

Capture - Keep What Resonates

Everything not saved will be lost. - Nintendo “Quit Screen” message

The first stage is making sure you are writing everything down. Whether it be a thought you have while in the shower or an idea that comes to you while reading a book.

These can come from external sources such as highlighted passages from books or articles you have read, key takeaways from the courses you have taken or even meeting notes.

There are also internal sources which can be used to feed your second brain. Such as, personal anecdotes, stories, childhood memories or reflections from daily journal entries.

For books, I use Readwise which not only syncs my highlights from Kindle books, you can also use it to capture highlights from physical books.

For articles and Twitter threads I am currently using Matter which then syncs with Readwise.

Readwise has plugins for most of the note-taking software such as Obsidian, so all your highlights automatically get synced.

Organise - Save For Actionability

The idea of the organise phase is to save data against the projects that you are working on, so all the information is right there when you are ready to be creative.

Most of the effort when it comes to writing a blog post or a book is in the research. If you could organise all your material before you begin, then you will save a lot of time context switching when you actually sit down to write.

Tiago breaks down the organisation of notes into 4 folders, which he gives the acronym PARA.


The Projects folder contains all the short-term efforts that you are currently working on. The key aspect of these projects are they have a definitive end date.

Example of short-term projects that might be in this folder:

  • A blog post you are writing
  • A YouTube video you are planning
  • A product that you are looking to buy and compare
  • Notes on a book you are currently reading
  • Insights on a course you are studying


The Areas folder is for topics that you are interested in but don’t have an immediate project that they are related to.

For example, if you have a blog about Health & Fitness, then anything related to that would go in to a separate folder in the Areas folder. If you are learning Software Development, then you might want a folder about that too.

The key difference between Areas and Projects is these are topics which you are actively involved with on a day-to-day basis, but are linked to a particular project.


The difference between the Resources and Areas is a little vague. Essentially, the Resources folder covers everything else that isn’t one of the other 2 folders above.

So maybe you have an interest in brewing beer. It is something you intend to do in the future, so you are gathering a few bits of information here and there.

You aren’t currently brewing any beer, so it won’t go in the Projects folder.

It isn’t part of your day-to-day life, so it doesn’t belong in the Areas folder either, so into Resources it goes.


The last folder is the Archives folder. This is where you move anything that is no longer relevant.

This might be items from the Projects folder you have completed or Areas and Resources that you are no longer interested in.

It doesn’t have to be finished to move to the Archives folder, if you are postponing it for an extended period, then it can move here too.

Where should your notes go?

When you are adding notes to your folders, the idea is to go in order of the PARA acronym. Projects first, then Areas, then Resources. Naturally, if you are going to add something straight to your archive then maybe it should be in your Second Brain to start with.

Notes should also flow between these folders. If you are working on a new blog post, it is fine to move some notes from Areas to Projects. When you are finished with that project, you can always move those notes back again.

Even if you forget to do this, and it ends up in the archive, the search features of most of the note applications are good enough to resurface it again.

Try not to spend too much effort in organising your second brain. The idea is for it to work for you, not be another source of resistance.

Distill - Find The Essence

To attain knowledge, add things every day. To attain wisdom, remove things every day. - Lao Tzu, ancient Chinese philosopher

The idea is not to capture everything and store it in your second brain verbatim. The point is for you to select just key highlights from the text you are reading and to put it down in your own words.

Taking highlights is not enough, you need to distill those down to the basic concepts. Imagine you loved a book so much that you end up with 10s of pages of highlights. When you come back to gain knowledge from these, you would be stuck re-reading all those pages. Yes, it would be quicker than reading the book again, but is that enough?

For example, if I have highlighted a few paragraphs from a book I was reading, in my first read through of this note I would highlight the sentences that best outline the point the author is trying to make.

In my second read through, I would bold the few words from my previous highlighted sentences that sum up what is being said.

In my third read through, I would rewrite a concise version in my own words of what the author has said.

Tiago has called the process Progressive Summarisation.

This might seem time-consuming but it doesn’t have to be done with all your notes, only those that you keep finding yourself coming back to.

Express - Show Your Work

The last step is to turns all this knowledge into something we can create and share with the world.

Verum ipsum factum (“We only know what we make”) - Giambattista Vico, Italian philosopher

Reading a good book can be satisfying in itself, but especially for readers of non-fiction books it is even more satisfying to take what you have learnt and create something with it.

The key purpose of the second brain is not to squirrel away all of your knowledge into a digital vault that only you are allowed to look at. It should be as others have called a digital garden where others can admire in its beauty and wisdom.

Some people go as far as publishing their digital notes as is. This is something you can do with both Notion and Obsidian (requires a paid subscription, though).

I wouldn’t go this far, but the notes I take help in giving me material for my blog posts, newsletter, and YouTube videos.

Use CODE and PARA as a Template

If you are struggling with making note-taking an active part of your life and are struggling to see the benefits, then give Tiago’s CODE and PARA templates a try.

The important thing is that you need to start, you can always adjust your process once you have started.

My own digital brain is loosely based on Tiago’s version but has deviated quite a bit since then and I have picked up a few tips and tricks from other books and sources I have read.

I will do a post in future about my own digital brain and how I have it structured and will put a link to it here when it is out.

🙏 Was this helpful? If you want to say thanks, I love coffee ☕️ , any support is appreciated.