The paper slip or card has long been used by individual researchers and by organizations to manage information, including the specialized form of the
card catalog.
Conrad Gessner (1516–1565) invented his own method of organization in which the individual notes could be rearranged at any time. In retrospect, his recommendation of gluing slips onto bound sheets was an innovation in moving from commonplace books to index cards as a form for scholarly information management. in his well-known handbook on excerpting methods (
De arte excerpendi, 1689). In 1767,
Carl Linnaeus used "little paper slips of a standard size" to record information for his research. Over 1,000 of Linnaeus's precursors to the modern
index card containing information collected from books and other publications and measuring five by three inches are housed at the
Linnean Society of London. The 1796
idyll Leben des Quintus Fixlein by
German Romantic writer
Jean Paul is structured according to the in which the protagonist keeps his autobiography. French scholars
Charles-Victor Langlois and
Charles Seignobos, in their
Introduction to the Study of History (1897), recommended that historians take notes on paper slips or cards, and they commented: "Every one admits nowadays that it is advisable to collect materials on separate cards or slips of paper." However, some decades later other scholars said that in America in the 1890s the card-file note-taking system was "still something of a novelty".
20th century Antonin Sertillanges' book
The Intellectual Life (1921) outlines in Chapter 7 a version of the card-file method. The book was published in French, and translated into English, in many editions over the span of 60 years. Sertillanges recommends against the previous patterns seen with commonplace books where one does note taking in books or on slips of paper which might be pasted into books as they don't "easily allow classification" or "readily lend themselves to use at the moment of writing". Homer C. Hockett's
Introduction to Research in American History (1931),
Sidney and
Beatrice Webb's
Methods of Social Study (1932), Carter Alexander's
How to Locate Educational Information and Data (four editions from 1935 to 1958), Cecil B. Williams's
A Research Manual (three editions from 1940 to 1963),
Louis R. Gottschalk's
Understanding History (1951), Chauncey Sanders's
An Introduction to Research in English Literary History (1952),
Jacques Barzun and
Henry F. Graff's
The Modern Researcher (six editions from 1957 to 2004), and
A Guide to Historical Method (three editions from 1969 to 1980) by Robert Jones Shafer and colleagues. A German-language manual on research methods that included instructions for a was
Technique of Scholarly Work (multiple editions from the 1930s to 1970) by . American historian
Frederic L. Paxson (1877–1948) filed notes on 3×5-inch paper slips daily throughout his career, and by the time of his death all the slips filled about 80 wooden file drawers. The notes were ordered chronologically and topically, with cross-references on each card to related subject headings, linking each subject through various stages in time. Though the project was terminated by Benjamin's death, it was later edited and published in a final form. French theorist, philosopher, and writer
Roland Barthes (1915–1980) kept a or index card file beginning in 1943 until his death. Curator Nathalie Léger has indicated that there are 12,250 slips in Roland Barthes's bequest at the
Institut Mémoires de l'édition contemporaine (IMEC).
Louis-Jean Calvet explains that in writing
Michelet, Barthes used his notes on index cards to try out various combinations of cards to both organize them as well as "to find correspondences between them". In addition to using his card file for producing his published works, Barthes also used his note taking system for teaching. His final course on the topic of
The Neutral, which he taught as a seminar at Collège de France, was contained in four bundles consisting of 800 cards which contained everything from notes, summaries, figures, and bibliographic entries. Published posthumously in 2010, Barthes's
Mourning Diary was created from a collection of 330 of his index cards focusing on his mourning following the death of his mother. The book jacket of the book prominently features one of his index cards from the collection. In a well known photo of Barthes in his office taken by
Henri Cartier-Bresson in 1963, the author is pictured with his card files on the shelf behind him. Starting in the 1940s, German philosopher and intellectual historian
Hans Blumenberg (1920–1996) compiled more than 30,000 cards into his , which now occupy 32 conservation boxes at the
German Literature Archive in Marbach. Blumenberg was inspired by the previous notetaking work and output of
Georg Christoph Lichtenberg who used
waste books or
sudelbücher as he called them. Argentine-Canadian philosopher and physicist
Mario Bunge (1919–2020), who published about 70 books and 540 articles, used index cards in boxes to teach and to write publications starting in the mid-1950s. 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 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). He linked the cards together by assigning each a unique index number based on a branching hierarchy. Luhmann described the as part of his research into
systems theory in the essay "". Other well known German users include
Arno Schmidt (who used a large card file to write
Zettels Traum, published in 1970),
Walter Kempowski,
Friedrich Kittler, and
Aby Warburg, whose works along with those of Paul, Blumenberg, and Luhmann appeared in the 2013 exhibition ". Machines of Fantasy" at the Museum of Modern Literature, Marbach am Neckar. Australian writer
Kate Grenville, in a chapter of
The Writing Book (1990) devoted to using "piles" of notes as part of the writing process, said that screenwriters are known to use index cards to help organise their scripts, and American writer
Anne Lamott devoted a chapter to a writer's use of index cards in her book
Bird by Bird (1994). German writer
Michael Ende kept a , and in 1994, a year prior to his death, he published
Michael Endes Zettelkasten: Skizzen und Notizen (translation: ''Michael Ende's File-card Box: Drafts and Notes''), an anthology of some of his writing as well as observations and
aphorisms from his card file. Twentieth-century American comedians
Phyllis Diller (with 52,000 3×5-inch index cards),
Joan Rivers (over a million 3×5-inch index cards),
Bob Hope (85,000 pages in files), and
George Carlin (paper notes in folders) were known for keeping joke or gag files throughout their careers. They often compiled their notes from scraps of paper, receipts, laundry lists, and matchbooks which served the function of
waste books. U.S. president
Ronald Reagan kept quotes and aphorisms which he frequently used for speeches in a card collection. == Literary references ==