"Telling these guys named Al King apart is like looking for a specific dune in the desert," a research assistant griped to his boss, vintage R&B blaring on a jukebox in the background. "That's a good image," the clever musicologist snapped, "because the guy you are looking for used to record for a label called Sahara!" Indeed, that is surely a better way of keeping track of this particular Al King than to think up some connection with Shirley, the name of another indie label that likewise put out his sides in the '60s and '70s. The collected Shirley and Sahara singles were rei...