This is a valuable book... [It] reflects a welcome trend toward a reassessment of the notions of meaning and visualization in contemporary science. -- Peter Holland, Nature Provides a concise but probing introduction into the fundamentals of quantum field theory... The reader who wishes to pursue the philosophical consequences that ensue when not only properties of things but the things themselves become subject to quantum superposition can do no better than to begin with Teller's book. Its combination of careful exposition and thoughtful philosophical critique is an ideal starting place for this inquiry. -- Lawrence Sklar, Foundations of Physics Paul Teller ... does here what philosophers do best ... : verbalizing abstruse scientific concepts and arguments to stimulate thoughtful discourse about fundamental ideas. -- Eugen Merzbacher, Physics Today This is a very readable book for initiates of relativity theory, nonrelativistic quantum mechanics, and the philosophical problems associated with the foundations of each. -- Choice