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Understanding Music Division Classmarks: About

A guide to the various classification systems used in the Music Division

Introduction: Where did NYPL's classmark system come from?

Soon after the New York Public Library was formed in 1895, its first director, John Shaw Billings, set about to determine a classification scheme for its holdings. Dissatisfied with existing systems, Billings created a unique and practical system that he felt reflected NYPL's needs.  Known as the Billings classification, it divided the Library's holdings by subject, and within each subject, what he saw as a systematic progression of knowledge. For the Music Division, the Billings system was in use until 1972, after which newly-acquired volumes were classified by the Fixed order system. (Materials acquired prior to 1972 retain their Billings call numbers. Book or music sets that began prior to 1972 also retain their Billings call numbers for subsequent volumes.)

For books about and works of music, the Billings classification designated all volumes to have a classification beginning with an asterisk (usually called "star" by staff) followed by an M:  *M

Successive letters subdivided the discipline into manageable sections.  These are detailed on the tabs following this one.


Prefixes, suffixes and other alterations

While the base classmark for a Music Division item acquired before 1972 consists of an asterisk followed by M and other letters, there can be alterations added to classmarks.


  • ** or D*: Some items have two asterisks (instead of one) preceding the M.  Sometimes the two asterisks are abbreviated as "D*" (that is, "double-star").  This was originally conceived as a way to designate volumes whose height were taller than ordinary.
  • 7-*M, or 8-*M or 9-*M: Preceding the *M wth a number was a way to indicate various heights of volumes.
  • Mus. Res.: Special Collections books and scores are preceded by the abbreviation Mus. Res. (remember to include the periods).



Call numbers (or classmarks) can have a variety of suffixes.  Some suffixes apply to only specifc classmarks; these are explained under the specific classmark on subsequent tabs.  (The first three suffixes below apply to all the Billings holdings throughout the New York Public Library.)

  • + or ++ or +++: These indicate oversized volumes.
  • box: The addition of the word "box" after a classmark indicates that the item is unbound and stored in a folder. (When the Music Division was first set up, these items were stored in a wooden cabinet known as "the box.")
  • p.v.: Pamphlet volume.  Years ago in library practice it was felt that the best way to house small pamphlets was to bind several of them together.  Those are known as a pamphlet volumes and have the suffix p.v. followed by two numbers: the first indicating which number volume, and the second indicating the location of the item within a volume. For example, *MI p.v.4 no. 9 indicates the ninth item in the fourth pamphlet volume with the classmark *MI.
  • —Amer. or (U.S.): When the Music Division acquired a curator of American music in the 1930s, it was decided to identify newly acquired books and scores containing American content with these suffixes. (There was no effort to retrospectively reclassify volumes of American music acquired before 1930.)

Browsing the collection online

Knowing the Billings classmark scheme enables one to browse the Catalog to view the collection as if viewing the volumes on the shelf. Using a call number search in the Classic Catalog ( one can perform a search on a Billings classification classmark and browse through the Division's holdings. This holds true for any of the prefixes used by the Division.   

Most Special Collections books, scores and periodicals acquired prior to 1972 also use the Billings classification system, with the prefix:  Mus. Res. To browse Music Division Special Collections books, scores, and periodicals, one can begin one's search with:  Mus. Res. *M.

Please remember that most of the Music Division's more than 100,000 scores acquired prior to 1972 are not in the online catalog and will not come up in a search. For questions and searches of these scores please contact the Division at:

Reference Librarians

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Music Division & Recorded Sound Reference Librarians
40 Lincoln Center Plaza (65th St and Columbus Ave)
Third Floor
New York, NY 10023
(212) 870-1625
Subjects: Performing Arts