This report on the use of mobile facilities in preschool instruction programs is divided into four parts. Part I describes the three major mobile preschool instruction programs. The Appalachia Preschool Program and Southeastern Education Laboratory's Readimobile Program are being field tested as possible strategies for the delivery of instructional services to rural children while the Florida Mobile Early Learning Program represents an approach to the preschool education of migrant children. Information presented includes background, physical description of the unit, description of the population, program operation, staffing and curriculum, evaluation, cost analysis, and a line drawing of the unit. Part II of the monograph deals with mobile preschool training programs. Part III describes selected elementary school mobile programs and one quasi-mobile preschool program. Part IV contains general conclusions and recommendations and attempts to deal with some of the major issues germane to mobile education, to synthesize the programs reviewed and give some idea of the state of the art in mobile preschool instruction, and to formulate some of the unanswered questions pertinent to the future development of similar programs. (Author/AJ)