The UMN Music Library organizes its books and scores according to the Library of Congress (LC) classification system. An LC call number for each book or score is displayed on a label on the spine or front cover. Understanding the information on the call numbers can help you find what you need more easily.

Let’s decode the four elements of the call number in the following example:

Author: Geneva H. Southall

Title: The Continuing Enslavement of Blind Tom, The Black Pianist-Composer (1865-1887)
ML417 .B78 S7 1979 V.2 Copy 3

Element 1: first letter(s)

  • The first letter(s) of an LC call number designate(s) the subject area and/or format. Most music scores and books are classified as follows:
    • M = music scores
    • ML = music literature (i.e., books about music, such as biographies, dictionaries, encyclopedias, histories, and so on)
    • MT = musical instruction, including analysis, performance techniques, orchestration, and other pedagogical topics
  • The Blind Tom example above belongs in the category of music literature (ML).
  • Some music-related materials fall into other LC classes, including the following:
    • BV = hymns
    • GV = dance music
    • KF = music business, music law
    • ND = art and music
    • PN = film music
    • PR = songs, ballads
    • TK = recording technology and techniques
  • Within each letter class, items are shelved in regular numerical order from the lowest to highest subject number (Element 2)


Element 2: subject numbers

  • The numbers immediately after the first letters designate different types of texts within the field of music. A detailed breakdown of all subject numbers used for music literature (ML1 - ML3930) can be found at this URL: <>.
  • In the Blind Tom example above, 417 indicates the biography of a pianist.
  • The subject numbers can appear on the same line as the first letters or immediately below them. Such differences do not affect an item's placement on the shelf.
  • Within each subject number, items are shelved in alphabetical order based on the first letter of the cutter number (Element 3).


Element 3: cutter number

  • The cutter number is an alpha-numeric combination (i.e., containing both letters & numbers) to indicate the author or the topic of a publication, thus allowing related works to be shelved together, which can make shelf-browsing a fruitful exercise.
  • In the above example, the cutter number .B78 is assigned to all books about Blind Tom in the ML 417s.
  • S7 is a second cutter number in the above example. It refers to the author of this biography, Geneva Southall.
  • The cutter number is often preceded by a decimal point, as in the above example. The presence or absence of a decimal point has no effect on the shelving order, but the numerals within the Cutter number are always interpreted as if a decimal point precedes them. Thus, a cutter number such as .K3935 would precede .K4 on the shelf – the reverse of what would happen if those were subject numbers (which are always placed in normal numerical order).
  • Cutter numbers are usually followed by additional information (Element 4).


Element 4: additional information

  • In the above example, 1979 (the year of publication) follows the second cutter number to distinguish this item from any other editions of the same title published earlier or later.
  • Further information may also be included, such as volume and series numbers; copy number; part name (e.g., Violin II, Bass Clarinet); Köchel, BWV, or opus numbers; and so on. In the above example, V.2 Copy 3 designates the library’s third copy of the second volume of this title.
  • Materials bearing such additional information are arranged alphabetically or numerically, depending on the nature of the information. In the ML and MT classes, numbers listed separately from a Cutter number (e.g., 1979 in the above example) normally precede letters; in the M class, it is more variable.