First Published in 1998. This is Volume I in the Sociology of Behaviour and Psychology series. This work was first written as a Ph..D. thesis and submitted to the University of Nottingham under the title 'Conscience and Psychopathy: an investigation into the nature and development of the conscience'. It explores the problems of definition and assessment as well as outlining the results of the assessments made from listening to forty tape-recorded interviews: twenty with subjects diagnosed as psychopaths and twenty with normal subjects, acting as a control group.