His earliest song-poem work was made for Sandy Stanton's Film City label in which he would build the entire track using a Chamberlin keyboard (a precursor to the mellotron).
Thornton, a promising jazz vocalist in the late 1950s and early 1960s, had fallen on hard times, while the latter two were ambitious singers and songwriters who had had material recorded in the C&W and R&B markets.
Keith, who was born into a religious household and was even a musical evangelist for a time, fell in with a hard-living crowd in Los Angeles during the late 1960s and early 1970s, experimenting with different psychedelics.
In December 1974, by which time he had moved over to Maury S. Rosen's MSR Records, Keith met his death on the Hollywood Freeway in Los Angeles.
According to an article in the Los Angeles Times (which ran on December 15, 1974) Keith was seen "leaping or falling from an overcrossing onto the Hollywood Freeway," and he "plunged down the Santa Monica Blvd.