Swedish saxophonist Mats Gustafsson’s pair of local concerts last year gave plenty of reason for pause. A free improviser with bulldozer power who also pays attention to detail is a rare thing, and his astonishing mastery of both ends of the spectrum never faltered. With complex logic, heart-stopping surprise, and assured fluidity, his dense stream of ideas flowed from one polarity to the other, occasionally fluttering breathlessly in between. The recently released Parrot Fish Eye (Okka Disk), a striking collection of duets with percussionist Michael Zerang and trios with bass clarinetist Gene Coleman and guitarist/accordionist Jim O’Rourke recorded here last year, proves Gustafsson is as flexible as they come. His jarring, distinctive machinations on soprano and baritone sax include impatient, knotty jags of sound that often explode with frustrated vocal punctuations–when he screams into his horn it’s hard not to jump a little. These jags work beautifully in miniature, as in the Zerang duets, where the percussionist eschews the traps in favor of small clackety objects. Gustafsson’s most extroverted playing last year was with saxophonist Ken Vandermark, bassist Kent Kessler, and drummer Steve Hunt, with whom he’ll reunite Saturday at Lunar Cabaret. Together they carried out fleet-footed, dense investigations of sheer power and quick interaction. On Thursday, October 19, he’ll duet with the phenomenal percussionist Hamid Drake, and their first ever meeting promises to be a stunning, highly intuitive trip through all manner of sonic extremes. If you’re picking up the paper on Thursday, October 12, you should also be aware that you can catch Gustafsson playing solo tonight at 7:30 amid the lovely acoustics of the Renaissance Society’s Cobb Hall, on the campus of the University of Chicago, 5811 S. Ellis (702-8670). Whatever you do, catch him at least once. Saturday, 10 PM, Lunar Cabaret and Full Moon Cafe, 2827 N. Lincoln; 327-6666. Thursday, October 19, 9 PM, Urbus Orbis, 1934 W. North; 252-4446.