Finnish composer Einojuhani Rautavaara began his musical education at Helsinki's Sibelius Academy, but on a recommendation from that school's namesake, he went on to study at Juilliard and with Aaron Copland and Roger Sessions. Afterward Rautavaara signed on with the European avant-garde, embracing its de rigueur leftism. His first opera, which paid tribute to the 1956 Hungarian uprising, was appropriately sharp and dissonant, while a later opera combined Mozartean classicism with a Kurt Weillish mix of sardonic ballads and jazz riffs. Anne Heider had never heard of the composer when she began scouting works for her chamber choir Bella Voce. But she was impressed by the intricate rhythms and textural variety of his Vigillia, a musical setting of the Finnish Orthodox liturgy for the eve of the feast of Saint John the Baptist; its two parts, Vespers and Matins, are sung during services at dusk and dawn. Vigillia was first presented in full in 1971, but the hour-long concert version, which will be given its local premiere here, wasn't performed until 1998. The work may test the group's stamina and versatility, but the choir's timbral range, balanced sound, and razor-sharp intonation should match up well with the composer's kaleidoscopic sonorities. Bella Voce will sing Vigillia in the original Finnish; Heider is the conductor. Friday, October 25, 8 PM, Saint Joseph's Church, 1747 Lake, Wilmette; Saturday, October 26, 7:30 PM, Grace Lutheran Church, 7300 W. Division, River Forest; Sunday, October 27, 3 PM, Saint James Cathedral, 65 E. Huron. 312-461-0723.