In this paper, "sexual assault" is defined as "any approach or action of a sexual nature involving the child which is unwanted and/or causes the child psychological discomfort or pain with more than transitory effect." Three levels of child-sexual-abuse prevention are identified: primary prevention which prevents the abuse before it occurs; secondary prevention which minimizes the harmful effects of child sexual abuse that has occurred; and tertiary prevention which involves intervention to prevent a cycle of abuse. The literature on knowledge pertinent to each prevention level is reviewed. A section on research and policy recommendations advises that support services should be provided to families in which research has shown that children are at risk for abuse; these include families under stress from poverty and poor housing and single-parent families at risk from predatory males or males with poor impulse control. Such families may be identified through the detection of vulnerable children. Schools are ideal places for such detection. Schools in high-risk neighborhoods should be given high priority for family-support programs that include specialized counselors, child-care workers, and community workers. Other recommendations address the research needed to target potential offenders and prevent them from offending. 16 references