In the 21st century learning should be continuously available. This book traces the evolution of year-round school schedules from 1840-1980 in the United States and documents the many innovative educational programs of the past. It also describes the status, philosophy, calendars, and strategies of the 1990s and offers forecasts for continuous learning approaches that may emerge by 2020. The book provides the rationales for replacing traditional school schedules and describes previous efforts to change the 9-month traditional calendar and future concepts of educational innovation. Contains 302 references arranged chronologically. (LMI)