Roger Bacon: heretic, occultist -- genius. In a Europe dominated by the narrow doctrines of Catholicism, Bacon was a man whose vision reached far beyond even our own day, a man who risked deadly accusations of heresy and black magic in his search for scientific truth. In this brilliant novel, set against a vividly realized backdrop of thirteenth-century England, Paris and Rome, James Blish recreates the life of this lonely prophet and suspected sorcerer.