Rachmaninoff isn't "easy-listening" either, but he was a 20th-century composer who wrote music as if the 20th century never happened. Playing the Second Piano Concerto at an afternoon performance with the National Symphony Orchestra last week, Raymond Lewenthal wore a morning coat and striped trousers, a Chevalier de l'Ordre des Artes et des Lettres pinned to his lapel.

"I believe that a concert should be an occasion," said the wildly coiffed Lewenthal, his garb clashing with the informal dress of the orchestra, and lending him the look of a 19th-century man. The Chevalier, a shiny beribboned medal, was presented to him by the French government for his efforts to revive the music of several neglected romantics.

Charles Henri Valentin Alkan, who lived during the time of Liszt and Chopin and died (legend has it) under a toppled bookcase, has commanded most of Lewenthal's attention. He collected all of Alkan's works -- mostly written for keyboard, though one choral piece is a march for a dead parrot -- and painstakingly studied his life.

"Very few have had the courage to play his music," said Lewenthal, who's writing an Alkan biography. "It's just so difficult. I have a great sympathy for Alkan, of course. It must have been a very sad life -- someone of that quality of talent who never received the appreciation he deserved."