Our books (third floor) and bound scores (fourth floor) are organized using the Library of Congress (LC) call number system. In that system, every call number begins with a letter or a two-letter sequence. Music scores begin with M, books about music history and literature start with ML, and books about the technique or teaching of music start with MT. Call numbers for books from other disciplines begin with other letters of the alphabet. M for music is unusually easy to remember in the LC system!
A number that refers to a narrower subject area follows the M, ML, or MT. For example, M22 is where you will find collections of solo piano music, ML410 is where you will find composer biographies, and MT380 is where you will find music about teaching or playing the clarinet.
Next comes a decimal point, followed by a letter and a number. The letter stands for the last name of the composer (or author) and, since many names start with the same letter, that letter will be followed by a number or string of numbers representing the next letter or letters in the last name. So, for example, in our library M22.B11 points to a collection of solo keyboard music by J.S. Bach, M22.B25 points to a collection of solo piano music by Bartok, and M22.B82 points to a collection of solo piano music by Brahms.
After that could follow another line (or lines) of information: a string of letters and numbers representing the title of the work, the year of publication, the opus (op.) number of the work, and/or the copy number (c.2, c.3, …) if we we have multiple copies of an item in our collection.
When you are looking on the shelf for a book or score with a particular call number, read the information in each line, top to bottom, in alpha-numeric order. For example, items with these call numbers would follow each other on the shelf from left to right:
M22 M22 M22 M22 M22 M22
.B11 .B11 .B25 .B82 .B82 .C54
W656 W656 P5 M32 M32 P25
1983 1983 1981 c.2 1983
Look for the call number ranges posted at the end of each shelving unit in the library.