This report provides a comprehensive review of the relatively new phenomenon of Internet-based drug treatment interventions (DTI). It presents a sample of Internet-based DTI programs across Europe and outlines their methodologies, providing a series of screenshots to further demonstrate the websites' content and to provide an overall impression of the types of online treatment available. This publication is a resource for researchers, policymakers and the general public, to gain an insight into the potential for the Internet to become a new channel for drug treatment intervention.--Publisher's description.