In 1812, William Croswell, an “early nineteenth century eccentric” – otherwise known for writing little-read, obscure books about astronomy, creating a well-received map of the stars (the first American star-map), and incurring debts to friends – was hired by Harvard to produce a new printed catalog for the library.
The library contained about 20,000 books, and was arranged by donor of the volumes.
Croswell apparently didn’t get on well with students, who played pranks on him including hanging a skeleton in the library. But he slowly and steadily progressed, until he had a list. He then began the task of putting it in a more logical order. Eventually in May of 1817 Croswell began cutting the list into strips, a task which took six weeks. Then he was able to arrange the slips under the appropriate headings.
Croswell eventually got fired for taking too long to finish the catalog.
But in 1840, librarian Thaddeus William Harris wrote that the Harvard Library should compile a slip catalog, listing all the collection’s titles on pieces of paper.
Harvard College Librarian Thaddeus William Harris urges in his 1840 annual report that a “slip catalogue” be created consisting of the title of every work in the library on pieces of card 6 1/2 inches long and 1 1/2 inches wide. Library historian Kenneth E. Carpenter (who put together a comprehensive history of the library in 1936 [PDF]) gives Croswell the credit.
Lists of a library’s inventory date back much farther, from writing on the walls to scrolls. Harvard at least claims their catalog is the first of its kind. The Encyclopedia of Library and Information Science says perhaps not and points back to Europe. The Harvard library was one of the first libraries to hire women, who hand-wrote many of the cards.