Geographers Lai, So Fun-Mun, and Ka-Wing Chan, all currently or formerly affiliated with the University of Hong Kong, work with field epidemiologists on geographical information systems (GIS) and remote sensing application in epidemiology and other environmental sciences. Here they offer simple facts with visual examples for readers interested in geographic and spatial analysis, but also provide step-by-step instruction on running GIS on selected freeware in order to encourage the use of GIS in the field with minimum software cost. They do also describe more complex procedures that they claim only proprietary software can accomplish. Annotation ©2008 Book News, Inc., Portland, OR (booknews.com)