The library recently purchased the online version of American National Biography. While not specifically a music resource, it is rich with music-related content.
If you are familiar with the more well-known (British) National Biography, this is a similar resource – an attempt to collect reliable biographical entries for Americans with significant contribution to history, invention, culture, and politics.
While the Grove Dictionary is still the best resource for music, as well as typically being the most thorough, there are some features of the American National Biography that are quite useful. For instance, if you look up Aaron Copland, it has an entry about 2000 words long, with linked cross-referenced entries that include people other than musicians. (Eisenhower, FDR, Martha Graham, in addition to the musicians and composers he worked with). This information within that context is useful when looking at a composer or musician as a historical or cultural figure, and not just at his or her music.
The entries also include a selected bibliography that is slightly easier to read than Grove, as well as a list of vetted online resources, something which Grove lacks!
American National Biography does tend to only include people who are no longer living, and is not comprehensive, since the editors get to pick who they feel has made a significant enough contribution. However the online version allows for more frequent updating than the print volumes did, so there is a chance that recently passed composers (such as Lou Harrison) may still be included.
For now, this is available through the All Databases page on the main library site, but as the music library’s site morphs into its new form, you will see it linked from several of the related course guides, and listed as a music reference resource.