Father-daughter incest, which accounts for 75 percent of all reported incest cases, is characterized. Its pattern typically shows a progression from fondling or exhibitionism to more intrusive forms of sexual behavior, a duration of many years, a lack of overt force, a delay in disclosure, and a retraction or inconsistent statement by the daughter. Explanations for these characteristics are offered, and participants in the incestuous relationship are characterized. Mothers of incest victims are described as passive, ill, or incapacitated, and sexually unresponsive to the father. Incestuous fathers are portrayed as aggressive, uninhibited, and as having a strong sex drive. The child in an incestuous relationship may exhibit behavior which indicates that incest is occurring, such as neurasthenia, clinical depression, and social isolation. Four types of statutes in the United States which prohibit incest are discussed: child sexual abuse statutes, incest statutes, child protection statutes, and statutes relating to domestic violence and sexual psychopaths. Benefits of early intervention in incestuous families are noted, and the importance of facilitating treatment for the whole family is emphasized. Finally, investigation of the abuse is addressed, as is the possibility of removing the child from the home and determining the appropriateness of prosecution. A response to incest that incorporates the strengths of all persons who wish to help these troubled families is suggested. Included is a list of 144 references.