- a German sociologists, who was a prolific note-taker
- Realized that notes are only as useful as its context - the network of associations, relationships and connections to other information
- He often found himself surprised by his notes, and found himself communicating with the database of notes and develop new ideas
- The system is made up of index cards (zettel) that could extend infinitely in any direction, each idea lives on one index card
- And subsequent idea that is part of the same topic is put on another index card, but it is tracked through a numbering system
- When the idea branches from one, he would add a suffix letter to the number
- So each index card has a unique number and that is associated with many other cards
- He said he only did what was easy, and published 58 books, which meant that because he already had all the notes writing long-form to him was easy