Psychopathy is the popular term for a mental disorder (technically Anti Social Personality Disorder as categorized by the DSM IV-R ) and loosely applied to anyone perceived as being socio-emotionally "detached", unaffected by humanity's values and common sensibilities. Hence, a total disregard for the possible consequences of their actions. There is still some discussion as to whether a sociopath is the same species, though they are popularly considered so, but lets not get too technical here.
The very simple purspose of this entry to develop an awareness of these personality types which we may unknowingly come across. Take heed: they come in all forms and not just the overtly gradiose, violent types of both history and Hollywood. As manipulation is their most-often used tool, they can even be the sly, subtle ones you meet and interact with each day!