The author describes what might be the typical evolution of a gang based on her research experience with East Los Angeles gangs. Gangs may start out as friendship groups of adolescents with common interests. As time passes, normal adolescent interests in partying and dating combine with street socialization and the gang value of defiance of authority leads the gang to accept or encourage drug use or property offenses. As members age, the clique begins to splinter, Some members marry and settle down, while others remain involved in the street lifestyle, often mired in drug use and finding only marginal, if any, employment. Soon another clique moves in and the evolution of the gang continues. This phenomenon of change over time is an important consideration when defining gangs and is closely tied to escalating gang violence, as each clique wants to match or outdo its predecessor clique in standing up for the gang name. The author also discusses differences in gangs from one place to another and from one ethnic group to another. She emphasizes that violence by individual gang members is not necessarily gang violence, and explains why this makes a difference. There is clear evidence that gang members deal drugs, and there is clear evidence that gang members who deal drugs may kill and be killed. But there is no clear evidence that gangs as a whole do either. Gangs and gang members do pose problems for their communities. But they represent problems within the communities, problems that are not going to be solved by the simple declaration that gangs are criminal conspiracies.