Introduction In this chapter, we examine those theories that integrate and expand upon the arguments of other theories to provide more robust explanations of crime. Integration involves the linking and synthesizing of different theories of crime causation in an attempt to discover why individuals commit crime or antisocial behavior. Integrative theories vary in their scope. For example, although some focus on particular types of behavior or offenders in social process modeling, others may focus on why most individuals desist from offending as they age or how individuals develop. They can generally be divided into two categories based on their emphasis: (1) developmental theories, which prioritize explanations of change over time within individual offenders and (2) multifactor theories, which focus on building an explanation of crime that crosscuts different layers of analysis.