Research Center Main Reading Room

About the Main Card Catalog

The Library of Congress Card Catalog

The Main Card Catalog, located in the Main Reading Room, contains subject, author, title, and some other cards for most books cataloged by the Library through 1980 (1978 for subject cards). Each work cataloged is represented by a card or set of cards showing the name of the author, the title of the book, the place of publication, the publisher, and the date of publication. This information is followed by the number of pages or volumes, a brief description of the illustrative material, and the height in centimeters. If the book is part of a series, the name of the series is shown in parentheses after the size. A call number, consisting of a combination of letters and numbers, appears in the upper left-hand corner of the card and/or is printed in the lower portion of the card.

There are numerous ways to look for a book in the catalog. The most common are:

  • The author. The author's last name or the name of the agency or organization responsible for the publication.
  • The title. The title will be typed in lowercase letters at the top of the card.
  • The subject. Subject terms used by the Library are listed in the Library of Congress Subject Headings, large red volumes which are found in the catalog areas. Subject cards are colored red on the top edge, and the subject headings are typed in capital letters at the top of the card. Subject entries in the card catalog may contain terms no longer employed by the Library.

The arrangement of entries in the card catalog is basically alphabetical. However, entries are not always filed in strict alphabetical order. As shown in the examples below, personal names are filed first, then place names, subject headings, and titles. For example:

Love, William (personal name)

Love, Connecticut place name

LOVE (subject heading)

LOVE--TERMINOLOGY (subject heading, subdivided)

LOVE, MATERNAL (subject heading, inverted)

Love Abounds (title)

Explore more about the origins, history, and continuing research value of the Library of Congress card catalog, the predecessor to the Library's current online catalog, through our research guide.

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Thomas Jefferson Building, LJ 100
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