Since he first took the podium at the Metropolitan Opera in 1971, James Levine has conducted almost 2,500 performances there -- a record number -- and his repertoire is equally staggering: 85 operas. He is noted for his collaboration with singers, but equally important is his work with the Met orchestra, which he has fine-tuned into one of the world's leading ensembles. In this interview, Mr. Levine taks about his remarkable career.