Abstract: Prevention is one of the first approaches to be mentioned when public debate and policy address drug use and drug-related problems. Regularly, measures of prevention are presented as a means to overcome existing or future problems. However, evidence of ‘what works’ in practice is often overlooked. Similarly, research has shown examples where preventive efforts produced no or detrimental effects. This publication will help steer efforts in the right direction. Using an empirically derived reference framework, it bridges the gaps between science, policy and practice. Based on an overview of existing standards in Europe and beyond, a number of highly respected experts from EU Member States and international organisations worked together to prepare the publication. More than 400 national experts and stakeholders were included in a Delphi panel study and in a number of focus groups, which produced in-depth discussions as well as a consensus on the most important recommendations. The European Commission provided the funding for the original project on prevention standards and its results are now published within the EMCDDA Manuals series. In this series, information, advice, and guidance are offered to professionals and practitioners. Well structured and with many useful tables and figures, this publication will help its users as they progress from a first needs assessment to the delivery of an intervention and its final evaluation. Correct implementation of prevention measures with evidence-based components and anchoring them within existing structures and services (or activities) is key to ensuring effectiveness and it helps to avoid unintended iatrogenic effects. This manual will provide valuable guidance in this respect and allow preventive interventions to reach their full potential.