Krzysztof Penderecki was once a leader of the musical avant-garde, a deliberate iconoclast who preached the gospel of the new and swore by complexity for its own sake. But unlike so many of his contemporaries in the 20th-century music world, Penderecki eventually responded to public distaste for the avant-garde by embracing tonality, even if only as a balm to soothe the ravaged ears of the modern listener. The composer’s willingness and ability to adapt to changing styles has made him one of the most in-demand artists of his era, and he continues to write new material constantly, even as his career enters its sixth decade.