Although Mastrofski is modest and scholarly in drawing inferences from an impressive body of research literature, his conclusions still harbor much speculation, since in the police field there are few continuous, systematic research projects that involve replication. It is difficult enough to anticipate social changes of the most direct sort. It is virtually impossible to determine how a multitude of unanticipated social changes would precisely impact policing. There is little data available on many of Mastrofski's topics, notably the impact of changes in police personnel and training on performance. Further, it is difficult to generalize from empirical studies of police agencies and trends in particular metropolitan areas. Bennett's attempt to present emerging new profiles of crime and criminals to which police must adapt their stratgies is virtually devoid of empirically based reasoning and is reflective more of a personal philosophy than an objective data analysis. An analysis of policing is best done historically and cross-culturally, so as to sharpen theories, data-gathering, and analysis. Such research should precede attempts at predicting trends and directions. 25 references