A central theme in the history of American education in the 20th century is the expansion of formal schooling for more children. This literature review surveys the research on the educational uses of time, with a focus on the quantity and quality of time that teachers and students spent in school and, to a lesser extent, students' out-of-school activities. The review was undertaken as the first stage of a study that identified and evaluated a collection of reforms designed to enhance learning by altering the amount of and/or the quality of time devoted to learning. Chapters summarize the research on the quantity of time in school, the quality of time in school, and the uses of nonschool time and its impact on academic achievement and social development among young children and adults. Each chapter concludes with a summary and references. (LMI)