Yehudi Menuhin could play difficult violin pieces by Mozart, Beethoven and Bach at age 7. He played in Carnegie Hall at 11. He was 12 when he made his first record. At 13, he'd played in the finest concert halls in Berlin, London, and Paris. At 19, he embarked on his first world tour – 110 concerts, 63 cities and 13 countries. Yet at 19 he couldn't play a simple A major scale or a basic three-octave arpeggio. And he'd never figured out music theory.