Chicago Symphony Orchestra Conductor Emeritus Pierre Boulez leads the Windy City's internationally renowned orchestra in Gustav Mahler's "Symphony No. 7," taped over two nights, October 14 and 15 for GREAT PERFORMANCES. Boulez replaces the orchestra's ailing Music Director Riccardo Muti who was to have led the orchestra in a different musical program over those nights. One of Chicago's most popular conductors, Boulez, winner of 26 Grammy Awards, is a composer, conductor, and tireless advocate for new music and one of the most important musical and intellectual figures of our time. He served as CSO's principal guest conductor - only the third person to hold that title - from 1995 until 2006, when he was named Helen Regenstein Conductor Emeritus.