Year-round schools are not a new phenomenon in American education. During the 19th century, cities such as Chicago, Boston, Washington, Cleveland, Buffalo, and Detroit held school sessions of 48 or more weeks per year. The traditional calendar is a misnomer; it came about primarily as a compromise between urban and rural legislators. Renewed interest in year-round schools became evident about the turn of the century because of the space and financial problems facing many school districts. Since the early 1960s, a variety of factors have led communities and school boards to consider, and sometimes to implement, year-round school operation. This report examines several educational programs of year-round school and their implementation. The report describes various types of year-round schools and identifies the objectives, impacts, promises, and criticisms of each model. The second report is an exhaustive bibliography on year-round schools including a summary of evaluation studies conducted on year-round programs. (NTIS)