Mosaic Select: Johnny Mercer (Mosaic, three CDs). The greatest lyricist of the pre-rock era was also a marvelously jazzy singer, and this new set, which contains 79 of the singles he cut for Capitol between 1942 and 1947, is the most representative cross-section of his Forties recordings ever to be issued on CD. Best of all are the tracks on which Mercer sings Mercer, including “Ac-Cent-Tchu-Ate the Positive,” “Any Place I Hang My Hat Is Home,” and “One for My Baby.” Also present and very much accounted for: the King Cole Trio, Jo Stafford and the Pied Pipers, Jack Teagarden, and a roomful of top Los Angeles session men (TT).