Typologies can be a useful investigative, assessment or treatment tool; however, they must be considered with caution. Typologies are not mutually exclusive, as sex offenders do not always specialize in a particular type of behavior. The best way in which to understand typologies of sex offenders is as a continuum rather than distinct, unique categories. These typologies are important because sex offenders with certain characteristics are more likely than others to recidivate. In this outline of the development of sex offender typologies over the last quarter century, the following typologies were found: (1) the most common type of rapist is one who is motivated by power and control; (2) child molesters with a high fixation level tend to have the highest level of deviant sexual arousal and the greatest numbers of victims; (3) compared to male sex offenders, female offenders are less likely to use force, are more likely to initiate their behavior at an earlier age than male offenders, and are more likely to commit their offense with others; (4) juveniles who victimize peers and adults often commit sexual offenses in conjunction with other criminal behavior; and (5) many cyber sex offenders have occupations that give them direct or indirect work with children, such as teachers, law enforcement officers, and religious leaders. Tables, references