Book excerpt: This book was first published in 1984. The role of time in school learning has long been a topic of interest to educationalists. So much so that in the United States, Carnegie Units (purely time based entities) are used to certify high school graduates and credit hours are the basic unit of college certification. In this book, contributors explore the role of time in school learning. In particular, American research has demonstrated that learning is a function of two time variables; the time actually spent learning, and the time needed to learn. The book presents an integrated synthesis of the developments in the understanding of time in school learning and shows how this can have a dramatic impact on the process of schooling.