Since his earliest days with the piano-prog duo Attila, Billy Joel has shown off his voracious music scholarship. He pays tribute to The Beatles' pop bliss and displays his nimble ivory-tickling on the opening to “Angry Young Man” as well as “Root Beer Rag”; he combines expansive jazz with evocative storytelling on “Zanzibar.” His endless curiosity about music's possibilities makes for a catalog full of surprising left turns.