In this issue of JAMA Internal Medicine, we launch a series on firearm violence. Since we announced the series,1 firearm violence in the United States has continued unabated. In June 2016, a mass shooting at the Pulse nightclub in Orlando, Florida, killed 49 people and wounded 53 others. As of October 15, 2016, Chicago had recorded more than 570 homicides this year, levels not seen since the 1990s. Shootings in which 4 or more people are injured or killed (including shooters) occur almost daily.