Using the baritone guitar that he played on his one previous solo guitar album, "One Quiet Night" (2003), Pat Metheny gently unwraps familiar pop melodies from the '60s and early '70s on "What's It All About," his first album of all covers. The songs are all familiar-"Cherish," "And I Love Her," "Betcha By Golly, Wow"-and reflective of top 40 radio when Carly Simon could be part of a segue that included the Stylistics and the Carpenters. Metheny's choices, in song selection and his interpretive style, favor soft balladry, save for the surf-rock classic "Pipeline," which he turns into an absorbing instrumental not that far removed from Paul Simon's "The Sound of Silence," on which he's dutifully respectful of the tune's melodic and rhythmic structure. It's not the challenging listening experience that such recent albums as "Orchestrion" (2010) and "The Way Up" (2005) provided, but "What's It All About" is Metheny at his most genteel. The best moments occur when he stretches out, pushing Burt Bacharach's melody on "Alfie" toward eight wistful minutes and giving "Rainy Days and Mondays" seven minutes of sweet melancholy.