Isaac Stern on William Kapell

..... a woundrously giften young pianist...........

he seemed to walk electrically; it was as if he needed only to touch the piano and it opened up to him. He was a brilliant, explosive virtuoso, a Promethean pianist. During the past two years, his perceptions had matured; his palette of colors and ideas, the inner substance of his music, had grown larger, and he was able to give every greater scope to his performances and develop more and more music of various kinds - classical, contemporary, romantic, impressionistic. There was literally no limit to his talent. He was headed for a major career, not only because of his intrinsic ability as a musician but also because he possessed what I call the "X" factor, the most important quality of personality, describably but unexplainable, that enables the performer to extend across the footlights and mesmerize the audience.