Professor Everett W. Hall's new book, Modern Science and Human Values, one of the most important to have appeared in the field of Value Theory in the last ten years, shares in rich measure the common characteristic of so many other “prolegomena” to the future discipline of values: it is almost maddeningly frustrating. It sees with crystal clearness the essence of the scientific method and describes it in brilliant detail, from Galileo to Einstein; but it fails to draw a positive moral for value theory. On the contrary, its thesis is thoroughly negative: although value must be known as thoroughly as fact if the world is to survive, the scientific method that has brought us knowledge of fact can never bring us knowledge of value. For fact and value are fundamentally different, fact is known by science in a way that excludes value, and hence, whatever may be the way by which value is to be known, it cannot be science. It is true, science has given the most powerful and incisive formulation to fact while value theory has done nothing of the sort for value. Value theory, therefore, must be brought up to the level of science, otherwise there is danger that we may perish under the impact of science. But how to bring this about, how to construct a value theory as powerful and as representative of value as science is of fact, that is the question which the book can only ask but not answer.