When people start collecting notes, the first instinct is to organise them into folders. It feels responsible. "Mindset" in one, "Business" in another, and everything neatly categorised.
I did exactly the same with email. In the early days of Microsoft Outlook, I tried to create a folder for every type of email I received. Filing each one took real mental effort, trying to find the most logical home. I'd end up with folders containing a single email because it didn't fit anywhere else. The whole thing felt odd: some folders bulging, some nearly empty.
Notes behave the same way.
The problem with one parent
Imagine you've written a note called Growth Mindset CEOs. Which folder does it go in?
It's about mindset. It's also about business. File it under Mindset and you'll miss it when you're working on Business. Duplicate it in both and you've created two things to maintain.
A file in a folder can only have one parent. That's the limitation. And the more sub-folders you add, the harder it gets to decide where something belongs. It becomes a cognitive tax every time you save a note.
Enter the Map of Content
A Map of Content (MoC) is just a note whose job is to organise other notes. It was popularised by Nick Milo of Linking Your Thinking, and it's an addition to the original Zettelkasten.
You create a note called "Mindset" and list the relevant notes inside it, usually as an outline:
- Mindset
- Fixed mindset
- Growth mindset
- Growth mindset attributes
- Growth mindset company
- Growth mindset managers
Now put Growth Mindset CEOs in your Mindset map and your Business map. Same note, two places, no duplication. The Zettelkasten sidesteps the whole categorisation problem by not forcing a single answer.
Why I love them
They give you hierarchy without the cage. Because a MoC is nested, you can zoom in and out. I can look at "Growth Mindset Company" at a high level or zoom into "Growth Mindset Managers".
They help you review. When I add a new note, I scan the relevant map. Is anything related? Does something need updating now that my understanding has changed?
They're a playground for new topics. Say you want to explore something but don't quite know what it will cover. Create a MoC and sketch what you think it might contain. It becomes a prompt for what to read next. As you add real notes, the outline evolves from vague to complete.
You can have loads of them. A note can appear in as many maps as you like.
Also known as...
You might see these called index notes or structure notes. They're essentially the same thing. An index note works like the index at the back of a book. A structure note is an entry point into a subject, with a hierarchy. A Map of Content can be either. Use whichever word you like.
The messy-box worry
"Won't it all get messy without folders?" It's a fair fear, and honestly the one I hear most. Here's my answer. Stop thinking of your notes as files in a folder and start thinking of them as entries in a database. You don't scroll through a database to find things. You query it: by map, by link, by tag, by search.
You can hold tens of thousands of notes this way without making your day-to-day any more complicated.
Try this
Pick a topic you know a little about. Create one note with its name as the title. Use an outline to list five to ten sub-topics you'd like to understand better. Leave it open. As you learn, add notes underneath. If you're completely new to the topic, borrow the table of contents of a good book to give yourself a skeleton.
What goes in a good Map of Content?
I use a repeatable structure: definitions, benefits, drawbacks, how-to, different roles, opinions, ideas and questions, and it makes starting a new topic far easier. In Atomic Note-Taking I share the template with a full worked example, plus the types of map you can create and how many you really need.
