Dixon's early sides show how attuned he was to American styles, as with the jazz-influenced swagger of “Pain in My Heart.” In later decades, his rate of songwriting slowed but his output as a bandleader kept pace, with songs like “The Same Thing,” from 1969's I Am the Blues, giving devotees a chance to hear his forceful, impassioned way of interpreting themes and textures that he'd already made a part of American lore.