Part I discusses the genesis and history of all major gangs; factors that influence the development and growth of street gangs in a community; and the typical organizational structure, hierarchy, and philosophy of identified street and prison gangs. One of the four chapters in Part I reviews theories of gang membership, with attention to hierarchy of needs, racism, socioeconomic pressure, family structure, and anomie. Theories of prevention focus on counseling programs, sports programs, educational programs, work experience, and the need for punishment. A second chapter defines "gang" as "a group of people that form an allegiance for a common purpose, and engage in unlawful or criminal activity." Perspectives on gang activity are presented for the general public, the news media, school officials, police, and gang members themselves. The chapter on gang structure and organization focuses on Hispanic street gangs, Black street gangs, stoner gangs, car clubs, Asian gangs, and prison gangs. The fourth chapter in Part I addresses gang communication and recognition through distinctive language forms, graffiti, clothing, tattoos, and hand signs. Part II focuses on the role of law enforcement and other components of the criminal justice system in dealing with gang violence and other illegal gang activities. Chapters on law enforcement provide guidelines for police specialization and gang-unit management, specialized patrol procedures that relate to gang contact and control, and specific investigative techniques. Attention is also given to guidelines for the effective prosecution of crime characteristic of gang activity. Extensive illustrative photos