5(Music Sales America). Learn the essential elements of music theory for vocalists performing contemporary music, be it jazz, pop, rock, gospel or R&B. This self-study book is for singers who aspire to perform or who may already be leading a band, going to jam sessions, or studying with a teacher, but who have not learned music theory and want to learn in a fun and interactive way. Online audio tracks are included so you can sing along as you learn the major scales and key signatures, and you can also use the background tracks provided for vocal improvisation.