Forensic Neuropsychology is a new and rapidly evolving subspecialty of clinical neuropsychology that applies neuropsychological principles and practices to matters that pertain to legal decision-making. Forensic neuropsychologists provide the trier of fact with specialized information regarding brain-behavior relationships. The primary responsibility of the forensic neuropsychologist is to provide information based on scientifically-validated neuropsychological principles and clinical methodology that is pertinent to the Forensic Question at hand—which is not just whether the patient has dysfunction, but whether the dysfunction results from the event under consideration. To best answer the Forensic Question, the neuropsychologist must use a methodology that has been scientifically-validated on brain-impaired individuals, and can distinguish various brain conditions from each other as well as from normal variation. The methodology must be able to determine whether any dysfunction found is, in fact, the result of a neurological condition as opposed to non-neurological, psychological, or even factitious disorders. This paper discusses neuropsychological methodology in the context of forensic application and the requirements of the legal process and illustrates these issues with case examples.