Many gangs do not last long, while more successful gangs excel at extending their economic base and recruiting new members. Eventually, well-established gangs may resemble organized crime groups. Large and well-organized gangs generally change tactics as their criminal focus evolves. With respect to possible reasons for gang establishment, most researchers agree that youth join gangs to satisfy needs unfulfilled in other aspects of their lives. These basic needs include structure, nurturing, economic opportunity, and a sense of belonging. Even so, the desire to meet needs does not fully explain the atmosphere of crime and violence that modern gangs foster. Images of expressive brutality are found in comic books, video games, movies, music, and television. Gang members are often fascinated by firearms, and media messages convey a strong link between violence and sexual attraction. Gang membership is a family tradition in some areas, and gangs have increased their involvement in drug trafficking. The gang problem requires a coordinated response by law enforcement, school, and community agencies and an understanding of social factors that produce and sustain gangs. The Federal Bureau of Investigation's response to gangs is discussed. 17 endnotes