An examination of geographic theories of social change clarifies how and why Torsten Haagerstrand's ideas have revolutionized geographic thinking, particularly regarding educational change and development, and provides the background for analyzing his models in detail. Haagerstrand developed the first formal geoqraphic model of diffusion processes, linking together certain macroconcepts which summarize the recurring characteristics of these processes--the growth curve and spatial expression of growth. The central ideas in geographic diffusion theory today are in large measure macroscopic in scale (excepting those patterned after Haagerstrand), relating to centers of innovation and spread, channels of spread, boundary effects, and receptivity factors. Haagerstrand developed three models, each a successively better means of simulating an actual diffusion process. Haagerstrand's formulations transformed geographical thinking, forcing geographers to focus on the processes producing spatial patterns in a behavioral framework, although the natural inclination of many geographers was to use his framework as a guideline for macroscale inquiries. Judith Meyer observed the parallels between education and diffusion, learning and adoption, and formulated a study of the diffusion of an educational innovation in the Haagerstrand framework. Haagerstrand's models and Meyer's work reveal several important aspects of the role of communication in social change for those interested in educational networking. (CWM)