In the "Adolescent Criminal" (Flowers, 1990), the "delinquent youth gang" was defined as "a loosely organized or disorganized group of juveniles distinguished by colors, race and ethnicity, neighborhood, and principles; and whose delinquent and criminal activities relate to status, respect, revenge, celebrity, satisfaction, and profit, and include murder, gang wars, and drug dealing." Studies indicate that a rapid growth in juvenile gangs and membership has occurred since the 1970's, when Miller (1980) estimated that there were approximately 2,200 gangs nationwide with 96,000 members in over 300 communities. More recently, the 1996 National Youth Gang Survey found the number of gangs and gang members to be much higher. This survey estimated that there were approximately 31,000 gangs with more than 846,000 members in approximately 4,800 jurisdictions in the United States in 1996. Studies show that the majority of youth gang members are between the ages of 10 and 24. Gang members are predominantly male and composed of racial and ethnic minorities, primarily African-Americans and Hispanics. Studies indicate that although not all gang activities are delinquent or criminal, youth gang members are more likely to be involved in criminal behavior than youths who are not gang-affiliated. A high percentage of homicides are gang-related, which has been attributed to illegal gun possession by gang members. Further, research has shown a relationship between youth gangs and various aspects of drug involvement, including drug abuse, drug sales, drug distribution, and drug trafficking. The correlation between juvenile gangs and school crime and violence has been documented as well. A number of theories have been proposed to explain youth gangs. Among the most influential are reaction-formation theory, opportunity theory, and lower class culture theory. Each of these theories is briefly explained in this chapter. 1 table and 3 figures