Most of the tracks come from Duke Ellington Just Jazz Concerts broadcasts from the Empire Room in Hollywood, February 1949. That's the Ellington band with Ben Webster (and Wendell Marshall on bass).
Singers were Ray Nance (Just Squeeze Me) , Kay Davis (Lover Man) and Al Hibbler (Solitude)
The Billie Holiday tracks were from another Just Jazz broadcast from LA in June 1949. Backing Billie were Neal Hefti on trumpet, Herbie Harper on trombone, Herbie Steward, clarinet and tenor, Jimmie Rowles on piano, Iggy Shevack on bass and Blinkie Garner on drums!