For the purpose of this study, organized crime is viewed as 'an ongoing criminal conspiracy or conspiracies intended to continue over the long term and involving a relatively structured group or set of interacting groups.' This definition encompasses not only the Mafia but other groups such as motorcycle gangs, the Mexican Mafia, La Nuestra Familia, the Black Mafia, and certain Colombian and Cuban criminal organizations. The study focuses first on La Cosa Nostra (Mafia), highlighting key events experienced or triggered by its members from 1890 through 1970. The remaining sections review the major activities of criminal organizations (La Cosa Nostra as well as other criminal groups): violence, corruption of public officials, narcotics trafficking, gambling, loansharking, theft and fencing, and incursions into the legitimate economy. In discussing each of these activities, the study details the scope and nature of the activity as well as the general law enforcement response to it. Chapter footnotes.