Most include photographs, discographies and sources for further reading. An excellent starting place for research in popular music that centers on performers. Be sure to use the cumulative index in the back of the last volume. The Encyclopedia of Popular Music . Brief biographical entries for popular musicians and musical groups.
Many entries contain discographies with release dates.
1980 Gleason, Harold, and Warren Becker. 20th-Century American Composers . Each entry includes biographical information, a list of works, a discussion of style, a quotation by the composer, and extensive bibliographical information. A dated, but nonetheless important, source. Who's Who in Music and Musician's Directory.