» 20th Century: 1900-Present
   Introduction to recent compositional work from Essentials of Music. Linked to details on historical themes, musical context, style, and living or recently deceased composer biographies.
   http://www.essentialsofmusic.com/eras/20thC.html

» Contemporary Music (1945 - 2000)
   Overview of the rise of technology and minimalism in late 20th century composition from The Conservatory at Humanities Web. Includes links to profiles of those involved in the period.
   http://humanitiesweb.org/human.php?s=c&p=i&a=l&ID=10

» List of 20th Century Classical Composers
   Wikipedia entry linked to individual biographical articles plus internal references and external links.
   http://en.wikipedia.org/wiki/List_of_20th_century_classical_composers

» Music History 102: The Twentieth Century
   Composers, major styles and developments, illustrations, and Real Audio RAM sound files from the Internet Public Library
   http://www.ipl.org/div/mushist/twen/index.htm

» The Late Twentieth Century
   General exploration of musical changes and experimentation in light of societal shifts during the period. Includes links to representative composers of the time.
   http://hem.passagen.se/alkerstj/worldofclassicalmusic/late20th/late_twentieth_century.html