Findings of the Supreme Court in Kansas v. Hendricks (1997) raise a number of issues related to public policy, law, and mental health. The purpose of this article is not to reargue these issues, which are covered in a number of articles in this special issue. Instead, the purpose is to review the clinical literature, empirical literature, and standards of assessment and treatment within the sex offender field and to examine how these impact implementation of the laws. This article outlines an approach to operationalizing the concept of mental abnormality and describes accepted assessment approaches, validated risk criteria, and currently acceptable treatment approaches. Limitations of researchers current knowledge about implementing sexual predator laws are also discussed.