Forensic psychology is a broad spectrum of topics related to both psychology and law issues. One of the more clinical issues involved in forensic psychology is the concept of criminal behaviour, in particular psychopathy. Although the construct of psychopathy has been the subject of a great deal of research, much still remains unclear. Biological factors such as genetics and HPA axis (re)activity seem to play an important role in the development of criminal psychopathic behaviour. The relationship between violence recidivism and psychopathy, and the fact that psychopaths lack moral emotions are important risk factors in the maintenance of criminal behaviour. Given the heterogeneity of psychopathic offenders, the effect of treatment still remains unclear. Consequently, the question arises whether we all are victims of our brain and, thus, treatment of criminal behaviour is useless. Or whether it is possible to alter criminal behaviour? In addition to this discussion, an overview of the content of this special issue will be presented. (Netherlands Journal of Psychology, 63,(112)(113)(114)(115)(116) Forensic psychology constitutes a broad spectrum of issues in the boarder context of psychology and law. For instance, it includes topics such as profiling, interrogation techniques, criminal behaviour, and eyewitness testimonies. This special issue 'Forensic psychology; new developments in theory and research', focuses on criminal behaviour, and in particular psychopathy. There are several motives behind choosing this specific topic. First, criminal violent behaviour represents the core issue within forensic psychology. Without criminals, there is no need for forensic psychologists. Secondly, criminal behaviour is a very complicated concept. Much is still unclear about the aetiology, development, and treatment of psychopathic offenders. Therefore, we have chosen to focus on the developmental aspects, risk factors and treatment of criminal, psychopathic behaviour. More specifically, this special issue highlights a number of topics from various themes. First developmental studies on psychopathic, criminal behaviour are included. These focus on young childhood (relationship with conduct disorder) and on adolescence (biological aspects). Since psychopathic traits in adults predict a particularly severe and violent pattern of antisocial behaviour that is resistant to many intervention approaches (Hart, Kropp & Hare, 1988;Harris & Rice, 2006;Serin, 1993), several articles are included in which the focus lies on the adult psychopath (relationship between psychopathy and violence, moral emotions, and brain imaging research of violent behaviour). Besides this developmental approach in which several aspects related to psychopathic behaviour are described in children, adolescents and adults, this special issue also includes a biological as well as a more cognitive line of approach in which most recent developments regarding theory and research of criminal behaviour are presented. Finally, the question whether criminal behaviour ca...