The National Drug Law Enforcement Research Fund sought tenders in 2002 for research to enhance law enforcement sector understanding of the structure and functioning of illicit drug markets in Australia - with a particular focus on illicit markets for prescription pharmaceuticals namely benzodiazepine and pharmaceutical opioids, their misuse and impact on crime in Victoria, Tasmania and the Northern Territory, where there is evidence of illicit prescription pharmaceutical markets. While the primary focus of the study remains on law enforcement interests in relation to licit and illicit benzodiazepine and pharmaceutical opioid markets, where warranted these are discussed in relation to the broader public health implications of the range of interventions potentially available as a response to the markets being examined, and their impact. This report presents a review of the literature, an overview of study methodology, key findings and jurisdiction-specific discussion points. The section outlining the key findings is structured according to the main study themes of market characteristics, diversion and links to crime, implications for police and other front line workers, and interventions. (Executive summary, edited)