Composed cognitive maps are a tool based on grounded theory and on Lynch's urban model of cognitive maps, which allow the transfer of information from ethnographic situations to general patterns, and to the so-called spatial dynamics. In criminological matters, they have been applied in the context of environmental and criminology of place to identify criminal situations, criminal patterns, and spatial dynamics of crime. The latter concept has allowed reliable diagnoses for the design of criminal policies. Their advantages are compared with traditional criminometric methods. It introduces a brief compilation of the existing literature on the subject. In a special way, this chapter shows how composed cognitive maps allowed the measurement of drug trafficking networks, police intelligence, and, above all, crime reduction.