The article presents an assessment of a number of prominent factors from the professional literature describing the background and clinical characteristics of paraphilic individuals and sex offenders. The factors include sexual history and preference, substance abuse, mental illness, personality and defensiveness, history of violence, neuropsychological impairment, and biological problems. The article reviews the reliability and validity of measures used, and suggests a battery of measures that offer some index of dangerousness and targets for treatment. The assessment package can be administered by a clinical psychologist and results in suggested guidelines for involving neurologists, endocrinologists, or other treatment specialists. The assessment usually requires two full work days for completion. Tables, references, notes