The premiere this week of Harrison Birtwistle’s Exody, a Chicago Symphony Orchestra commission, introduces to local audiences a British innovator still largely unheralded this side of the Atlantic. The belated recognition is hardly surprising, given that it took his own countrymen decades to discover him. Educated in Manchester–psychologically and culturally a long way from London–Birtwistle was part of the postwar Manchester New Music Group, formed by students eager to embrace ideas from the continent. But unlike two other members who later became prominent–Peter Maxwell Davies and Alexander Goehr–Birtwistle never ventured into 12-tone experiments or took up any other fashionable causes. Instead, he eked out a living as a clarinetist and teacher, keeping mostly to himself and writing music whose exotic, mercurial sonorities owe a debt to Var�se and whose intricate, teasing structures acknowledge a familiarity with Messiaen. Now an elder statesman at 64, he calls his compositions “music of imaginary landscapes,” in which, he says, “ideas are presented through the juxtaposition and repetition of static blocks.” The work he made his name on in England 25 years ago, The Triumph of Time (named for a Pieter Brueghel engraving), is a prime example: it unfolds gradually and unpredictably; the textures shift almost imperceptibly. It sounds tedious on paper, but it’s engrossing in performance, disclosing an offhanded yet impeccable logic. The same can be said about Birtwistle’s pieces for the stage (he’s affiliated with London’s National Theatre). In one, a ballad is sung over and over again, but with the subtlest changes of volume, accent, pace, and rhythm. Exody is supposed to suggest the experience of a labyrinth, one of Birtwistle’s favorite metaphors. Daniel Barenboim, who got to know Birtwistle through Pierre Boulez, conducts. Tchaikovsky’s Symphony no. 6, to be recorded for Teldec, rounds out the program. Friday, 1:30 PM, and Saturday and Tuesday, 8 PM, Orchestra Hall, Symphony Center, 220 S. Michigan; 312-294-3000. TED SHEN

Art accompanying story in printed newspaper (not available in this archive): Harrison Birtwistle photo.