Analyzing the system of offender profiling, this book takes into consideration the quality and validity of the information on which police base their decisions, assessing the possibilities for detecting deception. The consistencies of a criminal's behaviour are also studied, with a look at the differences between one offender and another. Other questions asked include what form such groups take and the influence they have on trhe criminal's actions, the role of leaders in crimes or the socio-cultural processes of which they are a part. There are also imortant issues about the implications and use of any answers that may emerge from scientific studies of crimes and their investigation.