A cream-of-the-crop sampling of her unearthed four-album live set from 1961 and 1962, these songs show Ella Fitzgerald ramping up her playful side onstage. She punctuates an already crowd-pleasing version of “Mack the Knife” with a loving Louis Armstrong impression and other thrilling improvisations, while “On a Slow Boat to China” finds her scatting as casually as a skipping schoolgirl. And of course she nails the ballads, too, bringing acute emotional focus to “I’m Glad There Is You” and “Deep Purple.”