Cutter numbers

Cutter numbers
Name	Cutter numbers
Classification	Library classification component
Inventor	Charles Ammi Cutter
Invented	Late 19th century
Related	Library of Congress Classification, Expansive Classification

Cutter numbers. A Cutter number is an alphanumeric code used in library cataloging to create a unique identifier for a book or other item, typically representing the author's name or the title of the work. Developed by librarian Charles Ammi Cutter for his Expansive Classification system, it provides a method for arranging materials alphabetically within a given classification number. This system enables precise shelving and retrieval, forming a critical part of the complete call number used in many libraries worldwide.

Definition and purpose

The primary function of a Cutter number is to achieve an alphabetical arrangement of materials within a shared subject category, as defined by a primary classification system like the Library of Congress Classification or the Dewey Decimal Classification. It translates an author's surname or a work's title into a concise code, allowing for the unique identification of individual items. This process supports the fundamental library principle of collocation, ensuring works by the same author are shelved together. The implementation of these codes is detailed in resources like the Library of Congress's *Cutter-Sanborn Three-Figure Author Table*.

Structure and composition

A standard Cutter number begins with a letter, almost always the first letter of the author's last name, followed by one or more Arabic numerals. The numbers are treated as decimals, not whole numbers, allowing for infinite expansion between letters. For example, the author "Smith" might be assigned the code .S65, while "Smythe" could receive .S69. For titles, the first letter of the first significant word (excluding articles) is used, such as .G72 for *"The Great Gatsby"*. Special rules govern prefixes like "Mc" or "St." and non-English names, as outlined in cataloging manuals like the *Anglo-American Cataloguing Rules*.

History and development

The system was created by Charles Ammi Cutter in the late 19th century as part of his innovative Expansive Classification system, which he developed while working at the Boston Athenæum. Cutter sought a more flexible and detailed method than existing systems for organizing library collections. His work profoundly influenced subsequent schemes, most notably the Library of Congress Classification, which adopted and formalized the use of Cutter numbers. The widespread adoption of this alphanumeric coding method marked a significant evolution in library science, moving beyond purely numeric or broad categorical systems.

Usage in library classification

In practice, a Cutter number is combined with a subject classification number to form a complete call number. For instance, a book about the American Civil War by author James M. McPherson might have the Library of Congress Classification number E468 and the Cutter .M23, resulting in the call number E468 .M23. This combination allows patrons and staff to locate a specific volume on shelves organized first by subject and then alphabetically by author. Major institutions like the New York Public Library and the University of Chicago Library rely on this system for organizing their vast collections.

Variations and extensions

The most common variation is the **Cutter-Sanborn number**, based on the *Cutter-Sanborn Three-Figure Author Table*, which provides a standardized, pre-computed list of number assignments for name sequences. Some libraries use a simplified version, sometimes called a "Cutter letter," using only the initial letter and a single digit. Furthermore, systems like the Sears List of Subject Headings often recommend Cutter number practices for smaller libraries. An extended application is the "double Cutter," where a second code is added for the title or a subject subdivision, allowing for even more granular arrangement within a collection.

Comparison with other call number systems

Unlike purely numeric systems like the Dewey Decimal Classification, which uses a decimal number for both subject and author (e.g., 813.54 for a specific American fiction author), Cutter numbers provide a distinct, alphabetical component. Compared to the Universal Decimal Classification, which relies heavily on punctuation and auxiliary signs, the Cutter system offers a more streamlined approach for author/title filing. While the Library of Congress Classification integrates Cutter numbers, other systems, such as the Bliss bibliographic classification or the Harvard-Yenching Classification, employ different, often proprietary, methods for achieving similar alphabetical ordering within subject classes.

Category:Library cataloging and classification Category:Library terminology