The Count himself died in 1984; but like several of the other big bands that established themselves in the 1930s to become jazz institutions, the Basie orchestra has remained alive, if not exactly intact. (The roster had grown somewhat fluid even under Basie, and at this point only three or four band members can boast any firsthand contact with their namesake.) But the Basie band has avoided the fate of so many such outfits--the precipitous decline into a ghost band, pallidly re-creating hits of 30 and 40 years ago--through the efforts of director Frank Foster. A tenor-sax star with Basie in the 1950s, Foster also contributed a number of terrific compositions and arrangements to the band's expansive book; returning to the organization in the late 80s, he quickly began to unearth wonderful, long-buried (and thus suddenly fresh) pieces that energized the band and its listeners. Still a potent soloist, Foster has continued to write new arrangements; he has also welcomed new works from the band's current members, thus echoing the spirit of Basie himself (as opposed to Duke Ellington, who maintained a stricter control over the band's material). The other soloists don't often match up to the legends that passed through the Basie portals--who could?--but they do cut their share of mustard. And Foster has honed the classic balance between powerful horn textures and elegantly simple rhythms that represents one of Basie's great contributions to orchestral jazz. On their most recent recording, Basie's Bag (Telarc), the band sounds simply and elegantly great. Wednesday, 7 PM, FitzGerald's, 6615 Roosevelt, Berwyn; 708-788-2118.