Background:

In 1891, with the implementation of AACR2, the Library of Congress began following the Library of Congress Filing Rules for arranging entries in its catalogs and publications, including the LC Classification and the shelflist. the following are some of the significant differences between the Library of Congress Filing Rules and earlier rules:

Abbreviations are filed exactly as they are written, not as if they were spelled out in full, e.g. St. is filed after Ss, not after Sains. Abbreviations that do not include periods are filed as if they were words, e.g. AMA is filed as Ama.

Initial articles and prefixes in personal and place names are treated as filing elements, e.g. El Paso is filed under E., not under P.

Numbers expressed in digits rather than in spelled-out form are filed before letters, e.g. 1990 is filed before the letter A rather than under N (as in Nineteen-ninety) or O (as in One thousand nine hundred ninety).

Hyphens are ignored in filing, and words connected by hyphens are filed as though they were two separate words.

Diacritics are ignored in filing, e.g. Hande is filed as Hande, not as Haende.

For the most part these rules have been "superimposed" upon previous filing arrangements, i.e. previously established or shelflisted entries have been retained as valid and only newly established or shelflisted entries have been filed according to the new rules. As a result, two filing systems can be observed within the classification schedules and the shelflist.

Procedures:

1.  Classification schedules:

Follow the Library of Congress Filing Rules to select the position of any new caption or Cutter being established within an alphabetical arrangement. Continue to use any existing number or Cutter that was established under earlier filing rules, even if its alphabetical position is not in accordance with current rules.

Literary author numbers:

Consider all existing literary author numbers as valid with respect to filing order, whether the numbers are printed in the P schedules or not, and whether they are arranged according to earlier or current rules. Arrange all new literary author numbers according to the Library of Congress Filing Rules.

2.  Shelflisting:  See G 100.

See also:

Subject Cataloging Manual - Classification: Contents