After a quarter of a century of rapid and sometimes spectacular growth, an increasing number of school systems are finding themselves faced with shrinking enrollments. The problems have changed from what to do about overcrowding, double sessions, and temporary facilities, to what to do about empty classrooms. The report examines this counter-phenomenon of shrinkage to find its extent, possible duration, and some of the strategies being developed to cope with surplus space. The authors interviewed over 100 school districts in 40 States and invited 25 of the larger cities to respond in writing to questions about their enrollment projections, whether they had excess space, and their plans for using it. The numbers needed to justify a decision to close a school form the basis of an analysis and recommendation. The report deals directly with how future population numbers are calculated and discusses the strategies and procedures that follow when a population is too thin for existing school facilities. (Author/MLF)