James Levine reveals his opening lineup for the Boston Symphony. “He is just past 60 and has more or less run the musical end of the Metropolitan Opera for more than 30 years. His health is both a mystery and a cause for concern. He walks gingerly and conducts sitting down. His musical energy, on the other hand, is as high as ever and his graphic if understated conducting style just as compelling. He talks as if he is planning on a long future.”