This chapter discusses various theories of criminology and crime statistics reporting in the United States. It introduces biological, psychological, and sociological explanations for criminal behavior. Sociological theories covered include social disorganization theory, differential association theory, and strain theory. The chapter also discusses conflict theories. It describes the development of victims' rights advocacy and the key government agencies that collect crime statistics, such as the Uniform Crime Reports, National Incident-Based Reporting System, and National Crime Victimization Survey. Clearance rates are defined as the percentage of crimes police solve.