The concepts of the 'urban village' and the 'urban fortress' express the opposing extremes of CPTED. The urban village model focuses on resident socialization as a means of preventing crime, particularly as it is fostered or inhibited by the physical design of the community. The urban fortress model involves securing buildings and environments to prevent access by outsiders. Viable CPTED models for most communities will lie somewhere between the urban village and the urban fortress models. An effective environmental design for a particular community involves cooperation between neighborhood planners and designers and the police. The police have an understanding of how environments are used or misused and by whom. In Canada, the Ministry of the Solicitor General and the Canada Mortgage and Housing Corporation are currently examining CPTED. Experiments will develop detailed principles for an urban design and property management approach to crime prevention in residential environments. The final product should include a guide for architects, city planners, developers, and others involved in the planning, construction, and management of housing. Recommendations are offered for research and development and awareness/training. Nineteen references are listed.