This commemorative book contains 10 papers that provide a selective sample of behavioral and social science research accomplishments and trends over a 50-year period, and comparisons are made with research presented in the 1933 report, "Recent Social Trends in the United States" (The Ogburn Report). Four chapters in part 1, "Understanding Social Change", highlight advances in theories and methods devoted to social, organizational, and economic change. They include: (1) "The Ogburn Vision Fifty Years Later" (N. Smelser); (2) "Measuring Social Change" (A. Reiss, Jr.); (3) "Uncertainity, Diversity, and Organizational Change" (N. Hannan); and (4) "Macroeconomic Modeling and Forecasting" (L. Klein). Part 2, "Numbers and Decisionmaking", features the increasing use of quantitative concepts and data. It contains: (1) "Public Statistics and Democratic Politics" (K. Prewitt); (2) "Deterrence in Criminology and Social Policy" (H. Ross, G. LaFree); and (3) "Choices, Values, and Frames" (D. Kahneman, A. Tversky). Part 3, "Discovering the Mind at Work", explores the growth of the study of cognition and behavior in: (1) "Changing Views of Cognitive Competence in the Young" (R. Gelman, A. Brown); (2) "Some Developments in Research on Language Behavior" (M. Studdert-Kennedy); and (3) "Visual Perception of Real and Represented Objects and Events" (J. Hochberg). References are included. (JHP)