This literature review begins with a discussion of the affiliative factors contributing to a person’s radicalization at the mass, group, and individual levels. Ideology does not seem to be “the” or possibly even “a” primary factor. The study continues with reasons for exiting, factors that may inhibit leaving an extremist group, and deradicalization efforts. Following these sections is a look at gangs and cults. It appears that deradicalization, deganging, and deprogramming efforts are not overly effective because they do not address the central affiliative factors important to the individual.