A gentle clearing of her throat and the speech of the audience fades into silence. Emboldened, the performer’s fingertips dance across the strings of her delicately tooled instrument—sending a trill of dramatic notes soaring over the rapt listeners. She draws a deep breath, and at precisely the right time her lips part as she accompanies the music in a perfectly pitched contralto. Beads of perspiration form on her brow from concentration, but she smiles to herself, knowing that she is playing the crowd just as skillfully as she plays the instrument in her hands.