https://en.wikipedia.org/wiki/Zettelkasten
German philosopher and cultural critic Walter Benjamin (1892–1940) used a card-file note-taking system with a numbering system to create his Arcades Projectwritten between 1927 and 1940.[35] Though the project was terminated by Benjamin's death, it was later edited and published in a final form.[36]
One researcher famous for his extensive use of the method was the German sociologist Niklas Luhmann (1927–1998). Starting in 1952–1953, Luhmann built up a Zettelkasten of some 90,000 index cards for his research, and credited it for enabling his extraordinarily prolific writing (including about 50 books and 550 articles).[46] He linked the cards together by assigning each a unique index number based on a branching hierarchy.[46] These index cards were digitized and made available online in 2019.[47] Luhmann described the Zettelkasten as part of his research into systems theory in the essay "Kommunikation mit Zettelkästen".[48]
