Jerry Bowles at Sequenza 21 poses an interesting question: who is the most underrated composer of the twentieth century? Kyle Gann and I agree on the same name: Carl Nielsen. For years, I've been waiting to write a Nielsen column for the New Yorker, but the occasion has refused to arrive. There are plenty of recordings, but live performances of the great Dane are rare, at least in this neck of the woods. Every couple of years, someone does the Fourth Symphony, the Inextinguishable, and that's it. (Danish for "Inextinguishable" is "Det uudslukkelige." When I was recently in Copenhagen, I had a strange urge to walk up to people and say, "Det uudslukkelige!" I did not.) The rhythmic power of the music is enormous. The Fourth is dynamic in the way that only Beethoven is dynamic. The Fifth, with its snarling snare-drum improvisation, is a half-hour explosion. The Sixth, the Sinfonia semplice, is a kind of meta-symphony, trumping Stravinsky at his own game. Try Herbert Blomstedt's two-disc set of the Fourth, Fifth, and Sixth. Although the really revelatory performances are live recordings by the likes of Thomas Jensen, Launy Grøndahl, and Erik Tuxen. This composer needs the drama of live performance.