The piano is essentially a percussion instrument. You press a key, a hammer hits the corresponding string, and a note is produced. But is that all there is? There must be more to playing the piano than that. Today, we'll hear from three terrific pianists, Vladimir Feltsman, Nelson Freire, and Garrick Ohlsson. Ohlsson weighs in on the difficulties of the piano, calling it "a box full of diminuendos." But with those three in the driver's seat, we prefer to think of it as a box full of exquisite possibilities.