Academic libraries use the Library of Congress Classification System to show a book's location on the shelf.
Look at call numbers and the Library of Congress Classification System for Music. Scroll to see the many subclasses.
The main categories are as follows:
Subclass M Music
Subclass ML Literature on Music
Subclass MT Instruction and Study
Some examples of subclasses for Music showing call number ranges
M 5-1490 Instrumental music
M 1495-5000 Vocal music
M 1999-2199 Sacred vocal music
M 2147-2155.6 Roman Catholic Church music
ML 100-109 Dictionaries, encyclopedias, etc.
ML 198-239 Writing on American music
ML 240-325 Writing on the music of Europe
ML 385-429 Biography
ML 459-1380 Writing on musical instruments
ML 1400-3275 Writing on vocal music
MT 1-5 History and criticism of music study
MT 90-146 Analysis and appreciation of musical works
MT 170-810 Instrumental techniques
MT 820-915 Singing and vocal techniques