Classic (pre-rock & roll) mainstream American pop performed either by individual singers or vocal groups. Traditionally the songs were written by professional songwriters and accompanied by an orchestra or a swinging big band.
From paper presented by Howard S. Becker at a 1994 conference discussing the structure of the standard popular song along with its history, songwriters, musicians, and singers. Bibliography. http://www.soc.ucsb.edu/faculty/hbecker/pops.html
Historic reviews and photos from performers of the 1940s, 50s, and 60s. Includes old time radio broadcast, quiz, and message board. http://www.bigbandsandbignames.com/
Collection of popular and classical sheet music from the 1800's to the 1940's, cover art, audio samples, composer biographies, and articles on the history, styles, and themes. http://parlorsongs.com/index.asp
Defines "melodic" genre as the vocal-oriented popular American music style that came after big band music but before rock and roll, as exemplified by singers like Perry Como and Margaret Whiting. http://en.wikipedia.org/wiki/Musical_genre#Melodic_music