from perfect, has been greatly enhanced in recent years. Whereas there was almost a vacuum of empirical knowledge ten years ago about the personality disorders, concentrated efforts have been undertaken to investigate classification, comorbidities, and expression of the personality disorders, and variants in normal personality traits. In addition, scientific advances in the fields of behavioral medicine, health psychology, and neuropsychology have greatly contributed to our knowledge of psychopathology and the interplay of psychobiological factors. It is now commonly acknowledged that psychopathology is not limited to the traditional mental illness categories; it also plays a significant role in many physical illnesses, such as cancer and AIDS. With these developments, it became clear that the first edition of this handbook was outdated and that a revision was needed.