Majority of US prisoners convicted of violent crimes at 62.5%. Murder convictions outnumber drug possession fivefold at 15% versus 3.2%. Median prior arrests for prison admittees is nine. Over 75% of prisoners have at least five prior arrests. Prisoners with 30+ prior arrests exceed those with none. Drug possession is only 3.2% of inmates even accounting for plea bargains. Prison population skewed toward serious long-sentence crimes unlike admissions. Criminals self-report 30 times more offenses than official records. Dark figure of crime vastly understates prisoners' true histories. US high incarceration stems from high serious crime rate despite development. US imprisons more per homicide than most nations. US has longer sentences than other developed countries. Violent offenders dominate even if all non-violent released US rate stays high. Incarceration reduces crime via incapacitation per causal studies. High crime and high prisons coexist like illness and medication.