New Grove Dictionary of Music & Musicians
Reference: 780.3 N42s2 (29 volumes)
The place to start for most musical topics. Thorough articles, extensive bibliographies, complete lists of composers' works.
New Grove Dictionary of American Music & Musicians
Reference: 781.773 N42h (4 volumes)
Oxford Companion to Music
Reference: 780.3 Ox2L
Edited by Alison Latham as a single-volume, 2002 revision of previous Companions.
American Musical Traditions
Reference: 781.62 Am3 (5 volumes)
Published in collaboration with the Smithsonian Folkways Archive, volumes include music of: Native Americans, African Americans, British Americans, European Americans, Latino and Asian-Americans.