IN the preface of this work, the author tells us that he “has tried to develop a philosophical interpretation of quantum physics which is free from metaphysics”; a somewhat puzzling sentence, since much of has treatment might properly be described as metaphysical, in the traditional meaning of the word. No doubt what is meant is that the book is concerned only with the epistemological side of metaphysics, and leaves ontology out of account; an attitude which will be widely approved, in a book designed primarily for the edification of physicists. Philosophic Foundations of Quantum Mechanics By Prof. Hans Reichenbach. Pp. x + 182. (Berkeley and Los Angeles: University of California Press; London: Cambridge University Press, 1944.) 3 dollars.