In the week this research synthesis was released by HFG, CNN reported that 45 mass shootings had occurred in the U.S. in the previous month. While not a new phenomenon, such violent events have again moved near the top of the American issue agenda. In Mass Shootings: Causes and Prevention, criminal justice journalist Mark Obbie presents key findings from leading research on mass shootings. Obbie summarizes a compendium of recent studies suggesting that restricting access to high-capacity weapons, building more effective early-warning systems, and creating a reliable process for data collection could greatly reduce the frequency and toll of this very American type of violence.