The Cutter number, or Cutter, is a combination of letters and numbers that follows the class number and is preceded by a decimal point.  This is not to be confused with the decimal number that may form part of the class number (such as QK477.2).  The Cutter number is most frequently based on the first word of the main entry, usually the author's surname.





Where double Cuttering is used, the second Cutter is sometimes known as the book or author number/Cutter, while the first is alternately the subject or class Cutter or, in the case of literature, the author Cutter.

Classification numbers may include a subarrangement consisting of a topical Cutter.  The topical Cutter, or its initial letter, is supplied by the cataloger.

The term Cutter is taken from the name Charles Ammi Cutter (1837-1903), who devised the Two-Figure Author Table in the closing years of the 19th century as an easy-to-use method of arranging books by author within a given class.  The Cutter Two-Figure Author Table and its subsequent expansion, the Cutter Three-Figure Author Table, have been adopted and used by libraries throughout the world.  In 1969, the Swanson-Swift revision of the edited and revised table was issued under the title Cutter-Sanborn Three-Figure Author Table (Swanson-Swift Revision).

Cutter's principles were modified to serve the special needs of the Library of Congress' rapidly expanding collections.  The Library's book numbers are therefore composed according to the Basic Cutter Table.  The book number is the part of the call number that distinguishes a particular work from others in the same class.  In the LC classification system, the book number is represented by the Cutter or part of the Cutter.

In the shelflist and on the shelf, the Cutter is the means by which an alphabetical arrangement of books is achieved.  This alphabetical arrangement is based on the LC filing rules (see G 100, Subject Cataloging Manual: Shelflisting) and the Preferred Shelflist Order Table (G 65, Subject Cataloging Manual: Shelflisting).

In order to permit infinite expansion between any two Cutter numbers, Cutters are treated as decimal numbers.  This means that for entries such as E41.B35 and E41.B4, .B35 is filed before .B4.

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LC Cutter Tables:  Contents