Twenty-one essays provide a perspective on the range and depth of current research in sociology. Almost all the authors are with departments of sociology in United States colleges and universities. One author is with a foreign institution of higher education and research, and a few are from American research centers. The essays fall into ten broad categories: differentiation and stratification, social processes, institutions, individual and society, urban sociology, demography, policy, theory and methods, historical sociology, and sociology of world regions. Titles include: Changing Patterns in Research on the Third World; Human Spatial Behavior; Mathematical Models in Sociology; The Comparative Sociology of Organizations; International Migration; Moral Order and Sociology of Law: Trends, Problems, and Prospects; Recent Trends in American Historical Demography; and The Social Organization of the Classroom. The volume concludes with cumulative indexes of authors and essay titles for each of the four annual reviews published to date. (AV)