This paper summarises the current research on the use of microsimulation and its use for understanding behaviour in modelling threat in society. The motivation for this project was to develop simulation tools that could be used to model human behaviour and overlay that behaviour with a full spectrum of threats to understand how alternative ways for undertaking prevention, protection and response could be used to reduce the risk from a threat. The basic simulation engine - Simulacron, and its associated modules are briefly described. A number of applications to biological infection, including single vector infectious disease spread, biological weapon placement in a community and multi-vector disease spread are also briefly discussed as examples as to how the basic modelling is developed1. While some preliminary work on interdiction of terrorism is discussed, the main thrust of the paper is toward the development of a general model of influence and behaviour that can be utilised with other modules of Simulacron. We believe that this simulation system, even though the tools are still in development, can be applied to a range of terrorism and crime related problems, including acts of terrorism and its indoctrination, the criminal terrorism fusion, criminal gang resource movement, critical infrastructure protection, interdiction and emergency response.