Every State has laws making child sexual abuse illegal and providing for civil and criminal penalties, although it is not clear that the laws are having their intended effects. Clinical definitions of child sexual abuse have involved several major approaches, with professional judgment sometimes required to define particular behavior as sexual abuse. Estimates of the incidence and prevalence of child sexual abuse vary widely, but it is clear that a large number of children are sexually abused. Child sexual abuse consists not only of specific sexual behaviors but also of actions the offender takes to gain access and control over the child, what is said to the child during the abuse, and the child's perception of the abuse and abuse context. Efforts to classify sex offenders in terms of personality profiles, the distinction between incest and pedophilia, the extent and nature of sexual arousal, and fixated or regressed types do not appear to be valid. Further research is needed regarding the victimization of specific children, victims' perceptions of offender, definitions, and policy responses to child sexual abuse. Tables and 47 references