The report, “Reducing Gun Violence: What Works, and What Can Be Done Now,” presents what PERF learned from researching gun violence and its convening of a national meeting of police chiefs and other experts in 2018. The main finding from an analysis of gun violence in the United States is that it consists of a number of different problems with differing causes, differing perpetrators, differing victims, and differing solutions. The problem is manifested in four types of gun violence: 1) suicides committed with guns; 2) daily criminal homicides and non-fatal shootings, which include drug-related and gang-related violence, killings as part of other crimes, interpersonal disputes, and other homicides; 3) domestic violence involving firearms; and 4) mass shootings. The report examines what is known about each category of gun violence and explores promising approaches that can be taken to prevent and reduce each type of gun violence. The report contains an action plan with nine recommendations for reducing gun violence. These include the certainty of punishment for illegal possession of a firearm, the implementation of evidence-based policing strategies to target the small number of offenders responsible for most gun violence, limitation on the availability of high-powered firearms, the assessment of threats to prevent mass shootings, and the expansion of gun-violence research. Online access to this report is provided in the article.