Skip to Main Content

A Guide to Music Research and Finding Music Resources

This guide will assist music users in finding music materials

How to Read Call Numbers

What a Call Number Includes

Library of Congress System
1). All call numbers begin with a letter, which stands for the subject area of the item

M = music scores
ML = books on music literature
MT = books on music teaching/music technique


The letters A-L and N-Z may also be found in the music library, since we have books about other disciplines, including ballet, art, history, and citation manuals.

2). Next comes a number prefix. It refers to a narrower subject area.
20 = Solo piano music
M20 is where you find scores for solo piano music

410 = composer biographies
ML410 is where you find music literature/books of composer biographies

655 = percussion
MT655 is where you find music teaching/ technique books for percussion

3). Next comes a decimal point, followed by a letter and a number.
The letter stands for the last name of the composer.
And, since many composers share the same letter (Mozart, Mahler, Mendelssohn), you’ll see a number as well, to distinguish between all these letter-sharing folks

In our library:
M84 = Mozart
M21 = Mahler
M46 = Mendelssohn

M20.M84 is probably a score for solo piano by Mozart
ML410.M21 is a biography of Mahler
MT655.M46 would be a percussion technique book by Mendelssohn, if it existed
(scroll down)



Go in order first by the prefix...
M21.M84 comes before

M465.S65 comes before

M25.5.T57 comes before
M26.T57 (watch out for that decimal point: 25.5 comes before 26, right?)

Then, alphabetical…
M21.M84 comes before
M21.S475, which comes before

Finally, by numerical order again
(remember, these are fractions, because there is a decimal point)

M21.M84 comes before
M21.M86, which comes before
M21.M866, which comes before
M21.M9 (remember, .866 comes before .9)

If your call number has yet another set of a letter and numbers, follow the same rules
M21.M84 A27 comes before
M21.M84 B12, which comes before
M21.M84 C42

sometimes an opus (op.) number, copy number (c.), and/OR year of publication might follow. For example:
M1503.R58 P37 1980 c.1
M77.T87 op. 53 1977 c. 2