The New Grove Dictionary of Music and Musicians is an invaluable resource for background on research on music topics. For help picking a topic consult this encyclopedia, located in the library Reference section. The Call Number indicates the location of these books on the shelf.
This is a big (29 volumes) set of books. The Index - at the back of Vol. 29 - will help you find the volumes and pages that discuss your topic (and related topics).
All content from the New Grove Dictionary of Music and Musicians, along with other sources, is included in the Oxford Online database below: