We present the epidemiologic history of firearms in the United States. Firearms are among the nation’s ten leading causes of death. Nearly one million firearm deaths occurred in the half-century 1933-1982. Suicide is the leading type of firearm death. Teenagers, young adults, and males 75 years old and older are currently at highest risk. An individual’s risk of suffering a firearm death has generally risen with age. Increased firearm availability is associated with increased rates of firearm homicide and suicide. Strategies to prevent firearm deaths and injuries should be formulated in light of these findings, and heightened efforts to design, implement, and evaluate preventive measures are urgently needed.