September 15

The Complete Guide to Building a Zettelkasten with Mem

The Zettelkasten Method is a powerful note-taking strategy that transforms the way you, read and write.

Most of us learned how to take notes by highlighting textbooks, memorizing the information, and regurgitating to the pass tests. Many people get through high school with good grades using this approach. But if you’re serious about How to be a Straight-A Student in college and thrive as a knowledge worker, it is not very effective.

Learning to take smart notes leads to an exponential increase in your capacity to remember what you learn, draw original insights, and produce new knowledge.

There are three underlying principles at the heart of a personal knowledge management system that enables you to maximize your output and create new knowledge.

  1. Externalization: As long as your knowledge lives inside your head, the value of it is limited.
  2. Contextual tags: By tagging your knowledge so you can retrieve it with minimal friction, you avoid context shifts that decrease your productivity and attention span
  3. Smart Notes and Networked Thought: Capturing notes on the information you consume and rewriting it in your own words makes your notes far more valuable for use in every intellectual endeavor. You end up with thousands of notes

While you could use several note-taking apps, Mem has become my tool of choice for executing these ideas.

1. Externalization

Sonkhe Ahrens says that “every intellectual endeavor begins with a note. Externalizing your knowledge is the foundation of a sound note-taking system. Externalized knowledge enables you to pursue intellectual endeavors, from writing a book to managing a project or running a company.

Writing a Book with the Zettelkasten

Let’s say you want to write a book. If your knowledge is not externalized, you have to sift through books, try to remember ideas, and think about how they might connect to the topic of your book. But if that knowledge is externalized in a system that you can access, it cuts the work down substantially.

Ryan Holiday’s notecard system is a physical version of externalized knowledge, in which he uses paper index cards and card boxes have made him one of the most prolific authors of our generation. Given that workflow is one of the most important predictors of professional success, I would argue that his workflow is the foundation of Ryan’s ability to be so prolific.

When you externalize knowledge, you can quickly retrieve relevant notes, identify topics you want to cover, and write an outline for a book.

Managing a Project with the Zettelkasten

The typical approach to project management is to have multiple resources spread across various tools. My old business partner Brian used to say that as content becomes more infinite, curation becomes more valuable. Today the same is true for apps and tools. This explains the emergence of all-in-one workspace apps like Notion, Roam, Walling, and Mem.

Focus shifts kill productivity and your ability to do deep work. Externalizing knowledge reduces focus shifts and increases productivity. It gives us access to every task, resource, and reference we need from one tool.

The Value of Externalizing Knowledge

Your brain is not a hard drive, and it’s a terrible place to store information. You want to use your brain to produce knowledge, not store it. Externalization is the key to retrieving and synthesizing information with minimal friction.

1. Externalization Makes Your Knowledge Easy to Search

Unless you have a photographic memory, it’s unlikely you’ll remember everything you’ve read. When you externalize knowledge in a note-taking tool that facilitates networked thought, you can do ALOT more with that knowledge. When you externalize your knowledge you can take it in new directions, which makes your knowledge more valuable.

Sure, you need to be smart to be successful in academia and writing. Still, if you don’t have an external system to think in and organize your thoughts, ideas, and collected facts or have no idea how to embed it in your overarching daily routines, the disadvantage is so enormous that it just can’t be compensated by a high IQ. – Sonkhe Ahrens, How to Take Smart Notes


As you’ll see from the image above, I have so many notes; the possibilities are kind of limitless. All I have to do is search for a topic.

2. Externalization Helps You Compensate for the Limitations of Your Brain

By externalizing your knowledge, you free up “space” inside your brain. The knowledge you externalize becomes what Tiago Forte calls your second brain. You’re also able to create links between notes and connect them to your existing lines of thought, projects, and ideas.

Attention is not our only limited resource. Our short-term memory is also limited. We need strategies not to waste its capacity with thoughts we can better delegate to an external system, Sonkhe Ahrens, How to Take Smart Notes

The less “space” knowledge takes up inside your mind, the more you have for coming up with new Ideas to Explore and Consider.

Externalizing Knowledge Allows to Take It In New Directions

By externalizing your knowledge, you can retrieve it, ask questions and interpret it differently because of Associative Networks in the brain.

When a representation remains inside our heads, there’s no mystery about what it signifies; it’s our thought, and so “there can be neither doubt nor ambiguity about what is intended,” notes Daniel Reisberg. Once we’ve placed it on the page, however, we can riff on it, play with it, take it in new directions; it can almost seem as if we ourselves didn’t make it. Annie Murhphy Hall, The Extended Mind

Externalized knowledge allows us to evolve our thinking each time we retrieve it.

2. Contextual Tags: The Key to Reducing Friction


Most people tag their notes by topic and use a folder structure. This makes knowledge challenging to retrieve. Tagging notes topic increases complexity and friction.

Most people try to reduce complexity by separating them into smaller stacks, piles, or separate folders. They sort their notes by topics and sub-topics, which makes it look less complex, but quickly becomes very complicated. Sonkhe Ahrens, How to Take Smart Notes

In his article on using tags for personal knowledge management, Tiago Forte recommends tagging notes by context instead of the topic. There are several advantages to organizing your notes by context.

Tagging Notes by Context Simplifies Your Workflow

When you tag notes by context, you can retrieve them with minimal friction. It also keeps your database of notes from becoming a giant mess, in which it’s impossible to find what you’re looking for.

The biggest advantage compared to a top-down storage system organized by topics is that the slip-box becomes more and more valuable the more it grows, instead of getting messy and confusing. If you sort by topic, you are faced with the dilemma of either adding more and more notes to one topic, which makes them increasingly hard to find or adding more and more topics and subtopics to it, which only shifts the mess to another level. Sonkhe Ahrens, How to Take Smart Notes

Tagging notes by context also frees you from the need for a rigid structure.

Tagging by Context Forces You to Act on Behalf of Your Future Self

When you tag your notes by context, it forces you to think about how you might use a note in the future, make connections between ideas, and generate new ones.

In the old system, the question is: Under which topic do I store this note? In the new system, the question is: In which context will I want to stumble upon it again? Sonkhe Ahrens, How to Take Smart Notes

Book Notes, Projects, Active, and In Progress are all examples of tagging notes by context.

I have many notes inside of my database for my podcast for The Unmistakable Creative Podcast #Unmistakable Creative Podcast.

#Unmistakable Creative Podcast is my context tag for each note, and other notes have tags like #interviews or #transcripts. I also tag notes with the name of the person I’m interviewing. I can search for notes from their books, transcripts of the interviews, and my takeaways for each episode with one click.

Every year I put together a round-up of what I’ve learned from guests on The Unmistakable Creative Podcast. This usually takes close to a month because I have to compile transcripts, book notes, and more from multiple sources. Because of contextual tags, something that used to take a month only takes a few hours.

Tagging notes by context speeds up your workflow and makes your system for maximizing creative output more efficient.

Using Topic and Context Tags Together

Rather than eliminating topic tags, it’s best to combine contextual tags and topic tags. The key is to tag by context first and topic second.

For example, say you’re reading Cal Newport’s book Deep Work. You might tag with something like #Book Notes #Deep Work #fixed schedule productivity. That way you could easily retrieve every individual note on that topic.

You can also do the same with projects with the following tags: Projects, Tasks, References, etc.

Match Tags to Structure of a Project

Say you are writing a book on note-taking and have a chapter about how to use tags. You would tag your notes with something like a book I’m writing, taking notes, using tags.

Everything you’ve written about how to use tags will be at your fingertips. If you looked inside my Mem database and searched for how to use tags, you’ll see this entire section of this article as a series of literature notes and permanent notes.

Using an organizational scheme use e that matches the structure of the project will make that project much easier to execute. –Tiago Forte,

When you use tags this way, it doesn’t just simplify your workflow. It reduces your effort and increases the speed at which you can create new knowledge exponentially.

Smart Notes and Networked Thought


The Zettelkasten method is based on the German social scientist Nicholas Luhmann’s work and was popularized by #Sonkhe Ahrens in his book How to Take Smart Notes.

Nicholas Luhman wrote 58 books and 500 papers and “turned to his slip-box and with its help he put together a doctoral thesis and the habilitation thesis in less tħan a year – while taking classes in sociology,” says Ahrens. As the son of a college professor, the idea that someone could complete a Ph.D. in a year sounded absurd to me. But as an author, I had to find out of it was too good to be true. And it turns out it’s not.

The principles I’ve shared above are contingent on networked thought, a slip box, and a specific workflow and structure for taking smart notes that makes it different than other note systems.

Networked Thought

Because of the Associative Networks in the brain, nothing that happens in the brain is linear. When you write a blog and come up with new ideas to write about, you make connections between ideas.

One easy way to understand the concept of networked thought is a jigsaw puzzle: you, CApture. Connect. Create and sort the pieces. Then you put them together. With this Note-Taking Strategy and approach to Knowledge Management, every task, insight, idea, or thought is a puzzle.

Because of bidirectional links, networked thought reduces friction between having insight and getting things done. It also enables you to build a system, so you never forget anything. But unlike the jigsaw puzzle, you can assemble the pieces in multiple ways, make connections between ideas and diversify your creative output.

The Slip Box: The Linchpin of the Zettelkasten

The collection of notes that you accumulate by taking notes with the structure above results in what’s known as a slip box. It’s a box of notes that anyone can use to become a prolific writer.

The Slip box Facilitates Networked Thought.

Because Your Brain is a network, not a hierarchy and because of bidirectional Links, instead of disconnected collection notes, you end up with a collection of ideas that are all connected.

What does help for true, useful learning is to connect a piece of information to as many meaningful contexts as possible, which is what we do when we connect our notes in the slip-box with other notes? Making these connections deliberately means building up a self-supporting network of interconnected ideas and facts that work reciprocally as cues for each other. Sonkhe Ahrens, How to Take Smart Notes

We need to be selective about adding bidirectional links when we make cross-references. Rather than just linking to the references based on tags, add links into your sentences, so they connect to your existing lines of thought.

In the digital version of the Zettelkasten, all we need to do is click on “Links” and add the number of the note we want to refer to. It then automatically adds a backlink to the note we refer from. Even though Zettelkasten makes suggestions here, too, for example, based on joint literature references, making good cross-references is a matter of serious thinking and a crucial part of the development of thoughts. Sonkhe Ahrens, How to Take Smart Notes

One Idea Per Note

The principle of atomicity is one of the core ideas of the Zettelkasten note-taking strategy. Each note contains a single idea. When we restrict ourselves to one idea per note, it makes each note more useful when combining it with other letters to create content.

By restricting ourselves to one format, we also limit ourselves to just one idea per note and force ourselves to be as precise and brief as possible. The restriction to one idea per note is also the precondition to recombine them freely later. Sonkhe Ahrens, How to Take Smart Notes

For example, every paragraph in this article was a combination of notes that each had a single idea.

Using Your Notes to Develop YOUR Ideas

Be selective about what you choose to write down. Resist the temptation to capture everything, and try to filter your note-taking relevant to your long-term thinking and the development of YOUR ideas.

Every time we read something, we decide on what is worth writing down and what is not. Every time we make a permanent note, we also made a decision about the aspects of a text we regarded as relevant for our longer-term thinking and relevant for the development of our ideas. We constantly make explicit how ideas and information connect with each other and turn them into literal connections between our notes. By doing this, we develop visible clusters of ideas that are now ready to be turned into manuscripts, Sonkhe Ahrens, How to Take Smart Notes

Knowledge management is not just storing references. When you store references, you’re not creating knowledge. You’re just storing information. If you can’t explain it in your own words, you don’t understand it.

Information becomes knowledge when you do something with what you’ve learned. Developing your ideas might involve writing about what you read, connecting it to existing projects, or creating links between notes.

Building Your Digital Zettelkasten


There are four primary building blocks to the Nicholas Luhmann created known as the Zettelkasten.

Fleeting Notes

While you’re reading, you will capture Fleeting notes. I recommend using a notebook for your fleeting notes and take paper notes.

Take a quick note and capture the idea. On each note, write down a page number and your insight. Review your fleeting notes once a day, or you’re likely to forget what they are about. Then you’ll turn fleeting notes into the literature.

Literature Notes

When you come across an idea or insight you want to remember, create a Note for it. Then rewrite it in your own words. This is important because Elaboration is Critical and Elaboration increases the odds of remembering what you read.

Before capturing all of the highlights from a book into one note, capture individual highlights into separate notes to create your literature notes. Link each note to the source.

“Making good cross-references is a matter of serious thinking and a crucial part of the development of thoughts,” says Ahrens. Your tags will show you all of the related notes in your note-taking app.

But your cross-references will be more valuable when you use bidirectional links as part of your sentences and link them to other relevant notes.

Another framework or model you can use for smart notes comes from Cal Newport’s book, How to be a Straight-A Student. Each note has three parts, Question, Evidence, Conclusion.

  1. Ask Questions about the material and generate an answer in your own words.
  2. Find evidence to support your answer. Often these will be the quotes you use.
  3. Draw some conclusion; this might be the title of your literature notes.

3. Permanent Notes

A permanent note is your primary insight. It’s something you can understand without context. You’d know what it was referring to in the future without knowing where it came from.

4. Reference Notes

Your reference notes are the original source or bibliographical notes: highlights from books, podcasts, etc. They would include the quotes you want to remember, passages you underlined, etc. For example, a reference not for a book would include the book title and all the highlights. The primary purpose of your reference note is to help you create permanent notes and literature notes.

Should You Refer to the Original Source?

This is a question that’s up for debate. There’s something to be said for trying to retrieve information without referring to the original sources. It forces you to think about how your notes might relate to your thinking and projects.

Rebecca Williams wrote a fantastic guide on the Zettelkasten method, in which she said, “When doing this, don’t look up the original idea on the page you got it from. Really try and write it in your own words yourself. It’ll make it really clear to you what you do and don’t understand yet, and also whether you want to invest the energy in filling those gaps.

For the sake of comparison, I’ve included two below. The first is a note in which I referred to the original source to create my literature notes. The second is one in which I didn’t.

The former became much more helpful after comparing the literature notes I wrote while referring to the original source and the ones I wrote without referring to the original source. What ultimately matters most is that you rewrite your literature notes in your own words.

Networked Thought and Smart Notes Lead to An Exponential Increase in the Creation of New Knowledge

Photographer: KMA .img | Source: Unsplash

I wrote most of this article on a Saturday night after drinking two glasses of wine. That’s not exactly a high-performance productivity hack.

  • By taking smart notes, your notes not only become more helpful in publishing new content. They lead to original insights based on your knowledge.
  • As you start to connect your ideas using tags and bi-directional links, that value of your knowledge and your database begins to compound.

Because I had an extensive collection of notes on the subject of note-taking, the only work I had to do was to supplement each area with examples (all of which I already had plenty of notes for). The quotes, sources, and research were already in my notes.

Your Notes Turn into the Raw Materials for an Idea Factory

Rather than being nothing more than a tool in which you store references, a tool like Mem becomes an idea factory. With every task, reference, and resource at your fingertips, the speed at which you complete a project increases exponentially. Not only does this enable you to maximize your output, but it also accelerates the pace at which you produce new knowledge.

Jennifer Louden once said to me, “your structure has to be linear, but your structure doesn’t.” In other words, you create the puzzle pieces, then put the puzzle together., Because Your Brain is a Network, Not a Hierarchy, tools like Mem allow you to write how your brain thinks.

You could lay the foundation for the first draft of blog posts or scholarly articles in under 10 minutes. But you never start with a blank page. The real work happens when you edit your content.

Networked thinking, combined with smart notes, leads to an exponential increase in creating new knowledge. It’s the end of writer’s block as you know it.

Every section of this article was based on a single note that was already inside my database.

I’ve used these notes to

  1. Produce all of the content for my note-taking course Maximum Output with Mem
  2. Write a landing page for the 100-Day Project
  3. An email sequence for another product launch
  4. Curate content for 14 days series featuring our best podcast episodes

All of this took less than ten days. If you get paid to produce ideas for a living, this approach turns you into a human idea factory. You’d be out of your mind not to use it.


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