Composers

Classical Composers Database: Life, Works, and Site links of numerous composers, organized alphabetically.

Composer homepages from Duke University: Music Librarian Scott Schlesinger's site is well organized and kept current. Composers are indexed by general historical period.
Composing and Composers: Primarily links to Composer Sites from the Sibelius Academy.

The J.S. Bach Home Page: Includes biography, bibliography, a works list, and a comprehensive list of links to other Bach-related sites, including organizations, festivals, worklists, bibliographies, etc.

Johannes Brahms: Includes brief biography, works list arranged by opus number, organizations, festivals, and a webography.

Composers: List of links from Indiana University.

Early Music by Women Composers: Chronological Index and substantial number of related links.

Hildegard von Bingen WWW Resources: Links for biography, her music and art, and lyrics.

Machaut: International Machaut Society: Biographies, texts and translations, discographies, and good links for other 14th century information.

Gustav Mahler: List of Works and links to other informative sites.

Mozart Project: The Life, Times, and Music of Wolfgang Amadeus Mozart Includes biography, works list, selected essays, bibliography, and other Mozart links.

Schubert Institute (UK): Contains biography, chronology, bibliography, and a works list arranged by genre.

Ralph Vaughan Williams Web Page: Contains a chronology, bibliography, links to other web resources, and a works list arranged by genre. 

Richard Wagner Archive: Biography, writings, quotations, compositions, bibliography, and other links.