The Mafia Monograph is the seminal document by which the FBI definitively declared in 1958 that "available evidence shows that beyond the shadow of a doubt, the Mafia does exist today in the United States, as well as in Sicily and Italy, as a vicious, evil, and tyrannical form of organized criminality."
The monograph was authored by the Central Research Section, and divided into two sections:
The first section is a study of the origin, nature, and activities of the Mafia in its native Sicily as a background to the Mafia in the United States. The second section explains how it was transplanted to the United States, sets forth its past and present activities in this country, and describes the form through which it continues.
The document served as notice on the heels of the Apalachin Meeting -- a summit in upstate New York among gangland bosses from across the nation which was busted by state troopers -- that the Bureau no longer was willing to tolerate business as usual from the Mafia, and it was widely disseminated with multiple copies to all field offices.
The FBI extensively detailed the assorted rackets with which the Mafia was involved across the country, and concluded that its most lucrative enterprise was heroin trafficking. The Sicilian clans gained their first U.S. toehold during the 1860s in New Orleans, New York and other port cities, and from the beginning the Mafia was smuggling heroin into the country according to the FBI:
About 1895, for example, the Mafia is known to have put up a recently arrived Sicilian immigrant to the United States in an olive oil importing business in order to smuggle narcotics into the United States. The narcotics were concealed in certain of the drums of oil arriving from Sicily. In 1939, the Federal Bureau of Narcotics of the U.S. Treasury Department was organized. Shortly thereafter, narcotics agents in tracing the illicit drug traffic from the peddler to his ultimate source came upon the Mafia and found it to have the monopoly of a drug smuggling racket that stretched across the Atlantic to origins in Sicily and Italy. At the Sicilian-Italian end of the axis, in the 1950s, were found such deported gangsters as Francisco Coppola, Serafino Mancuso, and Salvatore Lucania (Lucky Luciano); as well as the former narcotics fugitive Settimo (Sam) Accardi, all identified by the Narcotics Bureau as prominent Mafiosi.
The Monograph described narcotics trafficking as "a rich criminal business -- a small amount of heroin costing several hundred dollars abroad can conceivably bring $50,000 to $100,000 or even more in the illegal drug market when adulterated to expand its quantity," and "Mafiosi, naturally, have engaged extensively in this type of crime."