This chapter talks about the following 'types' of sexual offenders: exhibitionists, internet offenders, child sexual abusers/child molesters, rapists, and sexual murderers. It also discusses theories of sexual abuse, and risk assessment. The exhibitionists type is classed as non-contact because offenders do not physically touch the victim but instead typically expose their genitals from a distance. Internet offenders are a relatively new type of sexual offenders who have been charged or convicted of downloading illegal sexual material from the internet. Child molesters are often classified according to their relationship with the victim: intrafamilial/ extrafamilial; and/or gender of victim they target. Ward and Hudson have distinguished three levels of theory in sexual offending as follows: Level I (comprehensive) theories, Level II (single factor) theories and Level III (process) theories. The chapter concludes with a discussion on the main strategies used in the assessment of risk and treatment needed in sexual offenders.