This article introduces a special issue of Law and Human Behavior, including five articles describing the limits of forensic mental health assessments of (a) risk of violence in female adolescents, (b) sexually violent predators, (c) dangerousness in capital murder cases, (d) child sexual abuse, and (e) PTSD litigants. Knowing the limits of forensic mental health assessment methods is essential in order to recognize their strengths, increase the credibility of forensic mental health assessment, and drive research that will enhance the value of assessments for the courts.