This study evaluates the impact of the first year of "Sesame Street" on preschool televiewing audiences in five sites (Boston, Mass., Durham, N.C., Phoenix, Ariz., suburban Philadelphia, and northeastern California). Chapter I introduces evaluational questions and the research strategy. Chapter II presents sampling procedures for pretest and posttest data on 943 children, explains criteria for development and selection of measurement instruments assessing children's learning, program content, parent and teacher attitudes, and describes field operations. Chapter III analyzes results in three parts: (1) a descriptive analysis of the viewing population (age, sex, advantaged children, Spanish-speaking children, rural children, and disadvantaged at-home and in-school viewers), (2) a probing analysis investigating in depth the characteristics of at-home, disadvantaged, high-viewing children in relation to home background and high or low learning, (3) an inferential analysis examining the overall effectiveness of the television series in achieving its goals. Chapter IV presents the summary, conclusions and recommendations. Extensive appendixes include detailed information on "Sesame Street" goals and evaluation instruments. (WY)