A review of studies of the prevalence of child sexual abuse includes one by Finkelhor (1994), who surveyed the estimates of child sexual abuse in 21 countries, including the United States and Canada. All studies reported rates of abuse that were comparable to the rates in North American, ranging from 7 to 36 percent for women and 3 to 29 percent for men. An overview of the impact of child sexual abuse on its victims notes that when sexual abuse is an isolated incident, noninvasive, without physical violence, and perpetrated by a stranger, the child victim often can recover without major disruption to normal development. On the other hand, protracted abuse perpetrated by a member of the nuclear, extended, step, or foster family yields psychiatric sequelae in a variety of maladaptive outcomes. Regarding offender characteristics, one of the few indisputable conclusions about child molesters is that they constitute a markedly heterogeneous group. Their childhood and developmental experiences, adult competencies, and criminal histories differ considerably, as do the motives that underlie their sexual abuse of children and the behavioral patterns of their offenses. This fact makes it important that assessment and diagnosis reduce this heterogeneity by assigning the offender to a class or group of individuals with similar relevant characteristics. This paper reviews various diagnostic instruments for use of child molesters. This is followed by an overview of various treatment techniques that have been used with this population of offenders. 3 tables and 261 references