Call Number Guide: Introduction

What is a call number?

In the library world, the term "call number" can be defined as a unique address for any item held by the library, with specific characteristics in its formulation. Every physical item in the library is assigned a call number that pinpoints its location on the shelf.

What system do we use?

Here at the Peter Jay Sharp Library, we use a modified version of the Dewey Decimal System. This classification system has been around since the beginning of the modern public library, and in turn has become synonymous with the word "library".

In a nutshell, the Dewey Decimal System is grouped into ten main subject buckets, denoted by a 3 digit range (e.g. 000-099, 100-199, etc.). Further subdivisions within each bucket are done by the use of decimals. Depending on the granularity of the subject matter, these decimals can get rather lengthy. 

Our cataloging policy, for the sake of our and our patrons' sanity, is to keep the decimal places to a maximum of 4, and only then in specific areas of our catalog. 

How to read a call number

Call numbers should be read from top to bottom. Each level of the call number, or "cutter," represents a higher level of specificity to the item's location.

Following the initial Dewey class, the call number can have anywhere from 2 to 5 cutters. Most cutters will have a letter followed by a series of numbers that represent a specific word (e.g. M939 is "Mozart").

The first of these cutters can be either: the surname of the main contributor (composer or author), the topical subject (used in biographies and other special book categories), the first word of the title proper (without initial articles), or "A1" (denoting an anthology). 

The subsequent cutters can include the preferred title, enumeration, publisher, date, and/or editor. The combination of these varies based on the item type.

Please note: Sometimes, it can be difficult to distinguish a book from a score based on the call number alone, especially if you are unfamiliar with our system. For example, 786.4 refers to solo piano music, while 786.41 refers to books about solo piano music. While books and scores are in separate sections of the library, shelving mistakes can occasionally happen.