This volume is the result of a study, initiated by United Nations Educational, Scientific and Cultural Organization (UNESCO), to report on the main trends of social sciences research, not on the results achieved. Part I contains an examination of the present state and perspectives for development of the disciplines of sociology (Lazarsfeld), political science (Mackenzie), psychology (Piaget), economics (UNESCO secretariat, based upon work by Lange, Brus, Kowalik, and Sachs), demography (Bourgeois-Pichat), and linguistics (Jakobson). Part II contains four studies concerning interdisciplinary aspects of research. Piaget discusses general problems and common mechanisms of such studies, Boudon describes the trends of mathematical models, de Bie examines problem-focused research, and Rokkan distinguishes between cross-cultural, cross-societal and cross-national research. The concluding section contains a chapter by Trist on the organization and financing of research in the United States, Western and Eastern Europe. Piaget contributes an introductory essay on the place of the sciences of man in the system of sciences. (AL)