Of the many approaches to spatial analysis and visualization that have been developed over the past 30 years and applied to archaeological problems, arguably the most influential of these is the geographic information system (GIS). Despite its importance, there is at present no single volume treatment of the fundamentals of GIS written specifically for archaeologists and the unique problems they face in implementing them. This volume introduces GIS to archaeologists in a comprehensive and useful manner. The volume is divided into three sections: Section I defines GIS and places it into the broader context of spatial thinking in archaeology. Section II turns to more practical matters, including discussions of spatial data models and structures, projections and coordinate systems, sources of geographic data, geographic databases, and representation and visualization of geographic data. Section III illustrates how GIS has been applied in archaeology through a discussion of best practice, case studies that give the reader a sense of both the strengths and weaknesses of GIS in archaeological research. The volume concludes with a discussion of the future of GIS, and how archaeology can continue to take advantage of innovations of it.