This report summarizes a Unesco-sponsored study of indicators of international communication and socioeconomic development. Following a brief description of the background, purpose, and methodology of the study, the report discusses its findings in the following areas: (1) communication and social indicators; (2) communications and the growth of gross national product (GNP); (3) communications and development patterns for developed and developing nations; (4) other development indicators, such as population, literacy level, transportation, health, and employment; (5) changes occurring over a ten-year period in terms of communication, social, and economic growth; (6) time series data; (7) income distribution and economic dualism; and (8) investment and production in mass communications. Tables of data concerning communications indicators and basic indicators for 16 countries in five different GNP groups and a list of the 121 countries involved in the study are appended. (FL)