This book describes in detail the experience of professional personnel in the Atlanta City School System during two years of planning and five years of operating a year-round, four-quarter school plan involving 32,000 high school students. Content of the book focuses primarily on four areas concerning the year-round program: its beginning, development, implementation, and results. The final chapter offers sample quarter courses for seven subject areas. Arranged in table form, this section analyzes the content, concepts, behavioral objectives, and suggested procedures for each course and recommends useful references and aids for teachers. Although most of the book's content is derived from experience with the Atlanta year-round program, the ideas and procedures described will be of value to educators in other areas who are seeking a model year-round plan. (Author/JG)