"If I rest, I rust,” Plácido Domingo has been known to say. He is legendarily the busiest man in music. Valery Gergiev, the Russian conductor, is not far behind him, if behind at all. And he had a very busy—maybe typically busy—period in New York. He was at the Metropolitan Opera, conducting Boris Godunov. And he was in Carnegie Hall, leading his Mariinsky Orchestra, from St. Petersburg, in symphonies of Mahler. He will return to New York in February to conduct yet more Mahler symphonies, this time with another ensemble, the London Symphony Orchestra. (Gergiev serves this orchestra as “principal conductor.”) Why all this Mahler-ing? This year marks 150 years since his birth, and next year marks 100 years since his death. You get the impression that, without anniversaries, concert programmers would be paralyzed.

Over the years, I have remarked many times on the unevenness of Valery Gergiev....