There are no consensus definitions for gangs, gang members, and gang crimes, though the strengths and challenges of popular definitions  develop from core structural problems and individuals join gangs as a result of a variety of socioecological factors.

Meanwhile, gang violence occurs due to complex interplays between individuals and gangs. This chapter will delve into the historical development of gangs. Theoretical explanations for gang formation, gang joining, and gang desistence are examined along with the use of violence. Finally, attention is given to prevention of gangs, gang membership, and gang violence.