In many ways, Jo Stafford was the perfect female pop singer, if not the most beloved, for the between-wars generation in the U.S. With her warm mezzo-soprano voice, perfectly balanced tone, precise but flowing phrasing, and her girl-next-door image, she seemingly never made a misstep in her entire career, and if she isn’t as much a household name these days as contemporaries like Ella Fitzgerald, it isn’t because she couldn’t more than hold her own as a singer and entertainer. This 23-track set offers ample proof of that, although calling it “the Best of Jo Stafford” is a tad deceptive, since it contains none of the original Capitol Records versions of her biggest hits. What it consists of is rehearsal demos, V-discs, and radio performances done by Stafford between 1941 and 1950. That said, there’s nothing shabby about these recordings, and they highlight Stafford’s strengths as much as her official releases do. Most of the V-discs here were originally made at rehearsals for Johnny Mercer’s NBC radio show, Johnny Murcer’s Music Shop, including the lovely duet Stafford did with Mercer on his original composition “Conversation While Dancing,” which alone makes this set worth the price of admission. Also among the highlights here are Stafford’s perfect and haunting takes on jazz pop standards “Am I Blue” and “Dream a Little Dream of Me” (drawn from a performance Stafford did in 1950 for the Armed Services Radio program called Melody Hour), but every track is a quietly nuanced gem.