The focus on this project was to review the literature pertaining to the structure of criminal organizations and networks in order to ultimately identify the relevant variables that can then be applied to the development of analytical models. The identification of variables affecting the structures of and linkages between organizations will then serve as the basis for future statistical modeling that will enhance the understanding of these organizations/networks and inform strategies to disrupt them. The information provided in this report will help police and policy-makers to understand how specific features of individuals, groups and environments may help in the assessment of the scope and structure of organized crime in a particular setting.