For a long time Daniel Barenboim disliked much of Mahler--but then he became fascinated by the composer's fastidious notation, which demonstrated, as Barenboim wrote a few years ago, that Mahler was acutely aware of dynamics and was a "delicate and subtle" colorist. Barenboim conducted Mahler's Ninth Symphony for the first time last October, and one got the sense that he and the orchestra were discovering the work anew, finding an almost Wagnerian ebb and flow in the competing phrases and creating poetry in the final movement's exquisite farewell. He sometimes let secondary melodies wander, but such details will likely have been ironed out for this performance. Though he's still shaping his Mahler performances, Barenboim has been known for decades for his rhapsodic and intuitive interpretations of Mozart, and opening this program will be the Piano Concerto no. 23 with its touching central adagio. He's the only music director of a major American orchestra to conduct from the bench--one of his greatest strengths and most generous gifts to listeners. $40, $30, $20, $10. Sunday, June 20, 5 PM, Pavilion, Ravinia Festival, Green Bay and Lake Cook Rds., Highland Park; 847-266-5100.