Although it is often noted that Philip K. Dick is concerned with "the nature of reality," the assumption is usually that he is merely playing parlor tricks, that he is a clever sleight-of-hand artist whose entertainments are conjured out of thin air and exhibit little philosophy other than a fashionable nihilism or despair in the face of a universe thought too large and unregulated for comprehension. Yet Dick is far from being the unrelenting pessimist he is often considered. Rather, through his often dark vision he assumes a critical stance against the world-view that informs modern society; beyond this he presents a vision of a brighter world not beyond the reach of those informed of its possibility. But between unexamined reality and affirmed possibility lies an arduous journey: from the destruction of one world of knowledge to the creation of another. Dick's fiction is the story of this...