he didn't want to sing rock or r&b or anything like that. ♪ ♪ >> his introduction to the music world as a singer was in a vocal group, the moon glow. so he came out of the vocal group tradition of the '50s. >> he was schooled in the most kind of strenuous and exacting school of soul singing. we had incredible ears and had this kind of genius for harmony. he could sing all the parts. marvin joined motown, which is kind of a challenging thing. producers are in charge. and marvin didn't like anybody to be in charge of him. he had this acrimonious