From the Mormon Wars to the Border Wars to gangs of Bald Knobbers and Bushwhackers, Missouri's reign of vigilante justice during the nineteenth century is unparalleled by any other state in the nation. Situated as the Gateway to the West, Missouri experienced an influx of new cultures, races, and political factions, while already home to a population of patriotic war veterans. The state marked the boundary of eastern civilization and was a stronghold of fierce independence, bordered by Bloody Kansas and Native American territories. With new lands opening for settlement, and a fledgling system of law enforcement, the people themselves were compelled to invent laws and punish transgressors. Lawmen opposed vigilantes but at times were forced to cooperate with them and adopt their methods. Missouri spawned countless stories of individual and mob violence that finally ended at the turn of the century with advancing technology and the people's enduring insistence on decency and peace. Necessary Evil is the first book to chronicle the implications of vigilantism in Missouri, ultimately showing that the state could never have been settled without a healthy dose of rebel justice. Packed with stories of popular gunslingers such as Wyatt Earp, Wild Bill Hickok, and Jesse James, this action-filled read will be of interest to crime enthusiasts and historians alike.