"map plots "the history of 20th century music on the London Underground map devised by Harry Beck in 1933." Lines are renamed for music genres such as soul, reggae, pop, rock, jazz, hip-hop, electronica, and classical. Includes an article explaining how the map was plotted and many reader comments. From the Guardian Unlimited, the online companion to the British newspaper The Guardian." (via LII)

"Guide to books, articles, videos, magazines, and other material on hip hop, "a form of urban youth culture developed by African Americans and Latinos in New York in the seventies and eighties, originally in the Bronx." Covers music (DJing and MCing), the roots of hip hop music, break-dancing, graffiti, and related subjects. From the New York University Libraries." (via LII)

An ongoing, 50-plus-volume compendium of article-length biographies of popular music artists. Includes helpful lists for further reading.

A good source for dates, brief biographies, and discographies for popular-music artists.

The best place to start for research on classical music and jazz. Offers generous, well-researched articles by top scholars, and includes bibliographies of books and articles for further reading. Also available in print in the Marian Anderson Study Center (ML100 .N48 2001).