Over the past few years, Ann Hampton Callaway has evolved from a top cabaret singer into an ever-improving jazz one. She's got over her eager-puppylike tendency to overdo it (her scatting was often just too much). With Signature she痴 finally learned that simplicity is the hardest trick to master, but also the most rewarding. Backed by the likes of Wynton Marsalis, Kenny Barron, Frank Wess and Lewis Nash, Callaway goes over a series of standards associated with the likes of Sarah Vaughan, Billie Holiday, Tony Bennett, Nat King Cole and Ella Fitzgerald. Callaway puts her stamp on these songs: there痴 a newfound velvety smoothness and casual sense of ease to her voice and both are absolutely enchanting. Not only is this Callaway痴 finest achievement yet, but it痴 already one of the year痴 best jazz vocal records. --Elisabeth Vincentelli