Five strategies were used by the nine sites to reduce gun violence. One strategy targeted resources for geographic areas ("hot spots") where gun violence was persistent and concentrated. Another strategy targeted habitual offenders involved in gun violence in "hot spots." A third strategy used new technologies and advanced crime analysis in countering gun violence. A fourth strategy engaged appropriate community organizations in cooperative multi-pronged efforts to address gun violence. The fifth strategy consisted of the use of advanced problem analysis. Although many of the SPI projects are ongoing, several sites have produced important findings on outcomes, based on rigorous research methods. Boston's problem-oriented strategy that focused on micro-level "hot spots" reduced aggravated assault by just over 15 percent, violent crime by just over 17 percent, and robberies by approximately 19 percent. Baltimore's strategy of targeted enforcement within selected crime "hot spots" reduced homicides by 27 percent; and a related focused deterrence intervention reduced non-fatal shooting in one neighborhood by 40 percent. Baltimore's Gun Offender Registry reduced gun-related reoffending risks among participants by 92 percent. Los Angeles LASER initiative, which combined place and offender strategies with the use of criminal intelligence data, reduced homicides by just over 22 percent per month in the target division (Newton), and gun crime by 5 percent in each reporting district of the target division. The aforementioned SPI sites all used sophisticated evaluation research designs with comparison areas. This report also notes a number of next steps in countering gun violence, most notably the development of supply-side approaches that disrupt illicit gun-supply lines and combat illegal gun sales. 3 tables and descriptions of outcome evaluations in Boston, Baltimore, and Los Angeles