Every item in the Music Library has an "address" to help you find it on the shelf. This is the call number, which is a unique identifier made up of letters and numbers.
A typical call number looks like this. The various parts identify:
Type of Material (ML) - There are three types of music material: M, ML, and MT. M identifies sheet music, ML identifies music literature, and MT identifies music teaching and instruction.
Subject (410) - The subject describes the general topic of the item. In this case, ML410 denotes that this is a biography.
Topic (.O41) - This section is a code for the more specific topic of the item. In this case, .O41 is the code for biographies about Offenbach. All of the books about Offenbach are given this .O41 code and will be shelved together.
Author (G35) - This is a code for the author (in this case, Peter Gammond). If Peter Gammond wrote multiple books on this topic, they would appear next to each other on the shelf.
Year of Publication (1986) - The final element, the year of publication, is sometimes omitted.
A call number for a sound recording will differ slightly. A typical call number for a sound recording will look like this.
When locating a sound recording, the most important part of the call number to pay attention to is the type of material (in this case, MCD). In addition to telling us that this is a music recording, this area tells us its format:
You'll generally be looking for CDs, so you'll want the call number to begin with MCD.
If you're unsure what kind of format a sound recording is, the physical description portion of the record can help!
Depending on the item, its call number may be more or less complicated than the two examples above. However, the same basic principles apply for shelving by alphabetical and numerical order.
In addition to helping you locate where an item lives in the Music Library, call numbers group together items that are similar to one another. If you find one item that you like, there may be others right next to it that might also be worth checking out!