The monographs published from 1938 through 1970 under the general title of the International Encyclopedia of Unified Science are now published in two volumes (see also SE 012 543). The monographs included in this volume, and the philosophers who wrote them, are listed below. Foundations of the Social Sciences (Neurath); The Structure of Scientific Revolutions, Second Edition, Enlarged (Kuhn); Science and the Structure of Ethics (Edel); Theory of Valuation (Dewey); The Technique of Theory Construction (Woodger); Methodology of Mathematical Economics and Econometrics (Tintner); Fundamentals of Concept Formation in Empirical Science (Hempel); The Development of Rationalism and Empiricism (de Santillana and Zilsel); and The Development of Logical Empiricism (Joergensen). A classified bibliography, prepared by Feigl and Morris, listing other books including some published in the late 1960's, pertinent to the topics discussed in the monographs included in volumes one and two and an author and subject index to both volumes are included. (AL)