This book is based on the premise that research necessary to advance the utility of geographic informatior. systems must extend far beyond concerns with technical issues. The search for formalisms and generalizable principles relative to the behavior and needs of individuals, organizations and institutions is just as important in enabling optimal use of geographic information innovations. This book consists of papers prepared by participants in the NATO Advanced Research Workshop (ARW) on "Modeling the Diffusion and Use of Geographic Information Technologies. " The workshop was held AprilS-II, 1992, in Sounion, Greece. The idea for the workshop and this volume arose from discussions among U. S. and European researchers who had been involved in carrying out studies on the use and diffusion of geographic information innovations and actively involved in critically analyzing each other's work. We felt the time was ripe for reporting studies recently accomplished by the National Center for Geographic Information and Analysis (U. S. A. ), the Economic and Social Research Council (U. K. ), and others relative to these research topics. A workshop would allow contact among and international comparisons with those who were working independently on similar problems with similar or alternative approaches. It would also allow the bringing together of scholars in technology diffusion, management information systems, and sociology with scholars from the GIS community.