Charles Ammi Cutter (March 14, 1837 – September 6, 1903) was an American librarian.
Cutter was born in Boston, Massachusetts on the fourteenth day of March eighteen hundred and thirty seven. It was apparent from an early age that Cutter was destined for the library field. Not only was his aunt an employee of the regional library in Boston, but his rather frangible and gaunt anatomical structure in addition to his myopia offered him little interest in outdoor recreation yet allowed him to satiate himself in erudition. In 1856 Cutter was enrolled into Harvard Divinity School. Cutter was appointed assistant librarian of the divinity school while still a student there. Throughout the development of his curriculum, Cutter was appointed assistant librarian (in which capacity he served from 1857-1859) and began designing a distinct cataloging schema for the library's outdated system. The catalog, dating from 1840, had a lack of order after the recent acquisition of 4,000 volumes from the collection of Professor Gottfried Christian Friedrich Lücke of University of Göttingen, which added much depth to the Divinity School Library's collection. Along with classmate Charles Noyes Forbes, Cutter rearranged the library collection on the shelves into broad subject categories during the 1857-58 school year. During the winter break of 1858-59, they arranged the collection into a single listing alphabetically by author. This project was finished by the time Cutter graduated in 1859. In 1860; a year after graduation, Cutter was already a seasoned staff member of the library and now a full-time librarian where he became a journeyman to the chief cataloger and assistant librarian Dr. Ezra Abbot. Cutter worked as a librarian at Harvard College where he developed a new form of index catalog, using cards instead of published volumes, containing both an author index and a "classed catalog" or a rudimentary form of subject index.