This Encyclopedia is, first and foremost, the work of social scientists. It is part of the fabric of their professional literature their journals, annals, proceedings, monographs, treatises, textbooks, and expository writings. It has been planned by social scientists, and edited by social scientists. The writers, with a number of important exceptions, are social scientists. Social scientists will be the most frequent users, although undoubtedly they will be a minority among students, journalists, lawyers, legislators, administrators, educators, other professional people, and all the other users. Recognition of those responsible for the creation of the encyclopedia must, therefore, start with the social scientist themselves. Many perhaps even most of the leading social scientists of this generation have written it. Their work has been admirable, not only in its excellence but in its accommodation to the encyclopedia needs in content, exposition and schedule. Credit for the quality of the articles belongs to the authors.