According to Piero Scaruffi in "A History of Popular Music," unlike most pop music, arrangement and production is the key aspect of soul. Horns and lush string arrangements typify many soul records.
Soul music secularized gospel music, according to History-of-Rock.com. Artists like Ray Charles combined gospel singing styles with secular subject matter, often relating to women and sex.
Soul music, according to the All Music Guide to Soul, is commercialized rhythm & blues. It topped black and pop music charts during the 1960s.
According to Duke University Professor Mark Anthony Neal, the author of "Songs in the Key of Black Life: A Rhythm and Blues Nation," soul helped bring the black experience to a mainstream audience and influenced the civil rights movement.
Although a pop genre, soul follows the blues tradition. Its lyrics, singing style and sound are highly emotional and expressive, according to Oliver Wang, curator of "Soul Sides Volumes 1."