The sad blues for Chicago jazz is that the great ones leave. The Windy City has been home to many of the great musical innovators of the last four decades, but only a few resist the call of the East or the lure of University faculty positions. Fred Anderson, Kahil El'Zabar and Ed Wilkerson are among the handful of the AACM's first two generations still in Chicago (and Boston-born Windy City poster boy Ken Vandermark is in such demand that he's away much of the year). But as Delmark, 482 Music and a smattering of other labels are beginning to illustrate, the city is quietly simmering with new musicians.

Document Chicago features thirteen bands firmly in, yet challenging, the city's jazz heritage, and it's a good survey filled with great music. The Pavkovic Band (led by drummer David Pavkovic with vibraphonist Jason Adasiewicz, clarinetist Jonathan Doyle and cellist Diana Parmenter) create vibes and fractured lines a la Out to Lunch. The Exciting Trio (Pavkovic joined by guitarist Matt Schneider and Griffin Rodrigues on bass and electronics) take an unexpected ride. Adasiewicz and Doyle stage an intriguing melodica vs. vibes battle, tag teaming with saxophones, clarinet, drums, glockenspiel and organ. Grey Ghost (saxophonist Aram Shelton and drummer Jonathan Crawford, both also employing electronics) have a great electroacoustic sympathy, sounding something like an adrenaline-laced John Butcher. And the trio of saxophonist Matt Bauder, percussionist Jerome Byerton and pianist Alec Ramsdell (who died in 2002 at the age of 31) deliver a sweet sorrow.

Document Chicago captures a moment in time, one of those brief musical blossomings where musicians are bound together not just by proximity but by an enthusiasm to learn and to invent. They play in each other's bands and stridently make new from the old. Moments pass. Matana Roberts and Chad Taylor, who are featured here in the group Sticks and Stones, have already relocated to New York City. But in a way that wasn't clear several years ago, there's another generation lined up in the second city ready to keep the music alive.