Fifty years into his career, Van Morrison’s voice still penetrates. The selections on this loose, spirited duets album—shared with a bevy of R&B legends both British and American—don’t just celebrate Morrison’s catalog; they explore it. Morrison foregoes obvious picks like “Brown Eyed Girl” and “Into the Mystic” for lesser-known songs like the brooding “Streets of Arklow” (with Simply Red’s Mick Hucknall) and “How Could a Poor Boy,” a 2008 blues tune stretched out for a simmering six and a half minutes with the help of fellow journeyman Taj Mahal.