Despite the link between psychopathy and crime apparent in clinical descriptions, researchers generally have been rather pessimistic about the value of diagnoses of psychopathy in the prediction of criminal or violent behavior; however, it should be noted that this pessimism stems from a literature that historically was beset by methodological problems, not the least of which was the use of inadequate diagnostic procedures. The authors have spent the last decade developing improved methods to assess psychopathy culminating in the publication of the Psychopathy Checklist and its revision (PCL and PCL-R; Hare 1991). Recent research conducted with the use of the PCL and PCL- R, some of which is discussed in this chapter, suggests that the construct of psychopathy may indeed have predictive validity. The chapter begins with an abbreviated history of the PCL-R, which was the basis for development of the PCL:SV. It then reviews key research on psychopathy and violence. The authors conclude that the basic requirements they set for the development of a screening tool for the assessment of psychopathy have been met. The PCL:SV is conceptually and empirically related to the PCL-R; it is reliable and valid; it can be used with both civil and forensic populations, including the mentally disordered; and it requires relatively little time, effort, and training to administer and score. 7 tables and 48 references