Up until 1959, Dinah Washington was able to excel in every musical setting that she found herself. A strong jazz/blues vocalist who had many R&B hits, Washington always sounded confident and soulful even when backed by insipid studio orchestras. However after her Feb. 19, 1959 recording of "What a Diff'rence a Day Makes" became a major hit and she gained fame, Dinah Washington stuck to safely commercial pop music. Even when she was singing superior songs during the 1959-63 period, Washington was always backed by large orchestras outfitted with extremely commercial charts better suited to country pop stars. The sixth in Mercury's series of three-CD sets starts with the Feb. 19 session and covers 21 months in Dinah Washington's career. Most of the 73 performances are difficult to sit through.