Library of Congress

Cataloging Distribution Service

The Library of Congress > Cataloging Distribution Service > Product Categories

Search for Products and Services

Cataloging Resources, Manuals and Training Tools
More than a dozen of the Library’s most important cataloging and metadata resources are available in PDF and HTML formats in Classification Web Plus ( our web-based subscription service used by Library of Congress staff and catalogers throughout the world.

Classification Web Plus
The complete Library of Congress Classification system is available by subscribing to the web-based service, Classification Web ( Class Web also includes all Library of Congress subject and name headings.

MARC Distribution Services (data set)
Library of Congress cataloging records are available via FTP (File Transfer Protocol) delivery. Records are for materials in hundreds of languages, including non-roman alphabets in original scripts. MDS provides national level cataloging for almost all English-language imprints.

MARC Documentation
Machine-Readable Cataloging (MARC) is the standard in library automation. Available in Cataloger's Desktop (

Products with Free Downloads
As a service to the library community, free downloads of selected Library of Congress cataloging publications are now available at All MARC formats and other MARC documentation are available at

Subject Heading Authority Control
Available in various formats, these tools help you with subject access. The major subject authority publications include Library of Congress Subject Headings, Classification Web, and Subject Headings Manual and updates. Many of the publications are available in Classification Web ( and in Cataloger's Desktop (