Aretha Franklin is one of the giants of soul music, and indeed of American pop as a whole. More than any other performer, she epitomized soul at its most gospel-charged. Her astonishing run of late-’60s hits with Atlantic Records — “Respect,” “I Never Loved a Man,” “Chain of Fools,” “Baby I Love You,” “I Say a Little Prayer,” “Think,” “The House That Jack Built,” and several others — earned her the title “Lady Soul,” which she has worn uncontested ever since. Yet as much of an international institution as she’s become, much of her work — outside of her recordings for Atlantic in the late ’60s and early ’70s — is erratic and only fitfully inspired, making discretion a necessity when collecting her records.