PSN is a federal initiative that provides resources to localities and states for reducing gun and gang crime. The core of PSN consists of the funding of local programs coupled with an increased commitment by federal agencies to prosecute illegal gun use and possession. Since its inception in 2001, just over $2 billion has been committed to the PSN initiative. These resources have been used to hire new federal and state prosecutors, support investigators, provide training, deter juvenile gun crime, and develop and promote other gun-crime and gang-violence reduction strategies. All of the program evaluations summarized in this report have been selected from CrimeSolutions,gov and are publicly available in reports and academic journals. Research findings from PSN studies include highlighted findings from the PSN National Evaluation, PSN local-level studies, gang-crime reduction studies, and PSN-related studies. Summaries are also provided for evaluations reported in academic articles. These evaluations pertain to gang-focused and group-focused strategies, related anti-gang violence strategies, place-based strategies, "hot-spots" policing, PSN and offender reentry, and incident reviews and implementation capacity. This report is periodically updated.