Charting the Unknown presents a history of GIS technology that takes readers back more than four decades to the Harvard Laboratory for Computer Graphics and Spatial Analysis, where a variety of professionals converged to rethink thematic mapping, spatial analysis, and what we now call GIS. The book includes a CD containing interviews with important figures at the Harvard Laboratory, three movies showing animated visualization, and scanned copies of Context publications (from 1968 to 1983) describing research and research-related activities at the lab. Any current user of GIS technology will be fascinated to explore the complex origins of the GIS toolkit.