For the last 15 years of Jascha Heifetz's life, Ayke Agus was his closest companion. She came to him as a violin student in his master class at the University of Southern California, but he singled her out when he heard her play the piano. She became his private accompanist and ultimately his assistant and confidante. A sensitive and astute observer, Agus takes up where previous biographers left off; her book is a loving yet unblinking portrait of...