The Federal Bureau of Investigation has followed the activities of major motorcycle gangs and has confirmed gang involvement in drug manufacturing and distribution, prostitution, weapons-related violations, extortion, murder, arson for hire, pornography, protection rackets, loan sharking, interstate transport of stolen property and stolen motor vehicles, insurance fraud, and obstruction of justice. The importance of crowd control in preventing illegal or violent gang activities is emphasized, as well as the need to allay community fear of gangs and to deal with territorial disputes among gangs, crime conspiracies and enterprises, and gang security networks. The history of motorcycle gangs is reviewed, and a sociopsychological profile of these gangs is presented that focuses on gang member initiation, group structure, and female gang members. 54 footnotes