A comprehensive survey of the technology of mapping and its relationship to the battle against disease, this look at medical mapping advances a radical argument that maps are not merely representations of spatial realities but a way of thinking about relations between viral and bacterial communities, human hosts, and the environments in which diseases flourish. The history of medical mapping is traced€"from its growth in the 19th century during an era of trade and immigration to its renaissance in the 1990s during a new era of globalization. Referencing maps older than John Snow's famous cholera maps of London in the mid-19th century, this survey pulls from the plague maps of the 1600s, while addressing current issues concerning the ability of GIS technology to track diseases worldwide.