On May 13, 2000 the Chicago Underground Quartet played one of the most searing and transcendent sets of music I’ve ever witnessed, as part of the Empty Bottle Festival of Jazz & Improvised Music. Cornetist Rob Mazurek, guitarist Jeff Parker, drummer Chad Taylor, and bassist Noel Kupersmith performed with a fiery singularity of purpose, ripping through its set like a bulldozer, albeit a machine marked by nuance and soulfulness. The following year the same line-up—which had previously made two alb…