One day when he was seven years old, the prodigious Mischa Elman was asked to give a violin recital for some family friends. He selected Beethoven's Kreutser sonata, which he played with ease and considerable virtuosity.

During one of the piece's many pauses, one of his listeners, a kindly old woman, tapped Elman on the shoulder. "Dear," she whispered confidentially, "play something you know."