The first professionally trained librarian to be appointed to the position, L. Quincy Mumford worked for sixteen years at the New York Public Library and as Director of the Cleveland Public Library prior to becoming Librarian of Congress. In 1940, Librarian Archibald MacLeish asked Mumford to conduct an analysis of the Library of Congress cataloging system and processing operations. Mumford's report led to significant improvements in the Library's ability to manage the ever-increasing number of new materials.

In his twenty years as Librarian of Congress, L. Quincy Mumford updated and improved processing and cataloging methods at the Library of Congress. Mumford directed the development of the Library's first machine readable cataloguing, the MARC system, which was created by Henriette Avram. Mumford also called Congress' attention to the need for a new Library of Congress building by producing a report on the overcrowded conditions in the Main building and the Annex, as the Jefferson and Adams buildings were then called. The Mumford meeting and event room in the James Madison Memorial building is named in recognition of his contribution.

Quincy Mumford's papers contain just 750 items, mostly correspondence and writings relating to his appointment as Librarian, and related publications, reports, and ephemera.

The following titles link to fuller bibliographic information in the Library of Congress Online Catalog. Links to additional online content are included when available.