For many years, Karel Berka has worked at some of the central problems of the theory of the sciences. At once a logician, a mathematician, a careful student of the physical sciences and the social sciences, and a sharp but sympathetic critic of the major philosophies of science in this century, Berka brings to this treatise on measurement both his technical mastery and his historical sensitivity. We appreciate his careful analysis of his predecessors, notably Helmholtz, Campbell, Holder, Bridgman, Camap, Hempel, and Stevens, and of his contemporaries such as Brian Ellis and also Patrick Suppes and J. L. Zinnes. The issues to be clarified are familiar but still troubling: how to justify the conceptual transition from classification to a metric; how to explore ways to provide a quantitative understanding of a qualitative concept; indeed how to understand, and thereby control, the Galilean enthusiasm "to measure what is measurable and to try to render measurable what is not so as yet".