GIS are computerized systems designed to analyze geographic data. GIS include the combination of hardware, software, people, skills, and organizational processes necessary to handle geographic information, including data collection, display, integration, analysis, use, dissemination, and output. The chapter reviews the evolution of GIS from system to infrastructure, followed by a discussion of the importance of GIS to crime analysis and the strategic and tactical deployment of police resources in both the United States and the United Kingdom. Geographic profiling uses the geographic locations of a known series of crimes to assist in identifying the most likely area where the perpetrator of those crimes lives. The authors advise that the application of GIS to criminal investigation is in its infancy. The future should see the application of geographic analyses to all crime data and intelligence collected and recorded. One section of the chapter focuses on the assessment, examination, and comparison of neighborhood traits. Such analyses may provide information on the level and nature of the support an investigator may receive in different neighborhoods, as well as how best to engage with particular communities. 3 tables, 12 figures, and 49 references