For more than half a century, the renowned liberal thinker Sir Isaiah Berlin has occupied an important spot at the center of British intellectual and public life. Recipient of knighthood and the Order of Merit, he has been the head of an Oxford College and the director of the Royal Opera House. During World War II, he acted as Winston Churchill's eyes and ears in America. He is also a talented and prolific writer with five volumes of essays to his name. Surprisingly, John Gray's book is only the third full-length examination of one of this century's seminal thinkers.