Book summary: Building a Second Brain

Published:   Last updated: 2023-02-25


This article summarizes the Building a Second Brain book by Tiago Forte. The book describes the advantages of personal knowledge management (pkm) systems and offers many tips on using these systems efficiently.


Tiago organized the book around the four activities required for maintaining a pkm system that he describes using the CODE acronym, which stands for “Capture, Organize, Distill, Express.” Expression is the most crucial part of the process; all other steps exist to facilitate it.


Capturing is the process of adding new notes to your pkm. Tiago's primary recommendation is not to capture too much:

The dozen favorite problems technique is one way to filter out noise. Compile a list of the problems you are most interested in, which are dormant in your mind. Every time you read or hear a new result, run it against your problem list. If the result seems relevant to one of the problems on your list—capture it.


Tiago proposes an outcome-oriented organization system that he abbreviates as para. The crux of the method is classifying your notes into four top-level categories:

  1. Projects are short-term efforts with a goal and a deadline.
  2. Areas are long-term responsibilities that do not have a final goal, but they have a standard you want to meet. Finances, travel, health, and family are areas.
  3. Resources are topics of interest that might be useful in the future. Hobbies (music, calligraphy, etc.) and research subjects (geometry, type systems, cryptography, etc.) are good examples of resources.
  4. Archives contain inactive items from other categories.

One helpful analogy for the para system the book mentions is cooking in a kitchen:


One of Tiago's most insightful observations is that we usually find information not when we need it. Notes are like messages you send to your impatient and stressed future self. It pays off to distill helpful notes to their most essential points to facilitate their future use.

One technique that works well is progressive summarization:

Avoid common mistakes people make when applying this technique:

It pays off to be lazy. Instead of eagerly applying the summarization technique to every note you create, go one step further whenever you access the note. This way, you will spend time only on notes that matter and will not lose interest in the technique that requires up-front investment.


Attention is the most precious resource of knowledge workers. The purpose of the previous three activities is to help us stay focused when we enter the creative mode.

Tiago argues that most projects consist of smaller units or increments that he calls intermediate packets.” Use your pkm to track these knowledge pieces so you can find them quickly when you work on a project where they could be helpful. Strive to split your project into chunks and deliver them separately, receiving feedback as soon as possible.

According to Tiago, the creative process usually goes through two stages: divergence and convergence. During the divergence phase, we generate ideas and wander. During the convergence stage, we eliminate options and decide what is essential. Capture and Organize in CODE correspond to the divergence stage; Distill and Express—to the convergence stage.

Tiago also suggests three techniques to boost your creative output:

PKM habits

Tiago compares maintaining your pkm to mise en place, a set of habits that cooks use to keep their workplace clean and organized. He mentions a few helpful routines for managing a second brain: