The addictions field is populated by a wide range of stakeholder groups drawn from the public and private spheres and crossing disciplinary and occupational boundaries. Stakeholders have a key role in the formulation and delivery of policy and also in the production and dissemination of 'evidence' that is used to inform policy and practice. Increasingly, stakeholders and stakeholder networks have emerged and developed locally and nationally, but they also operate beyond national boundaries. These different stakeholders and stakeholder groups now play an important part in knowledge and policy transfer. Understanding the dynamics of stakeholder involvement in the policy process, and its role in relation to evidence-based policy, is important in examining policy responses to substance use and addiction. The purpose of this e-book is to critically examine local, national and/or supranational stakeholders' influence on policy processes. As you will see in the articles in this e-book, the complexity of stakeholder activity illustrates the need to map out the stakeholders relevant to a specific policy issue and contextualise their activities within the different national cultures and the political, health, economic and social systems in force at any particular time. The five articles comprise a number of case studies from different parts of the world, including Australia, Denmark, Norway and the UK. They draw on a range of theoretical frameworks to examine stakeholder dynamics at national and local levels, and focus on stakeholders in local alcohol policy, opioid substitution treatment, heroin assisted treatment, policy responses to alcohol-related violence and responses to prevention at schools. The aim is that this e-book will stimulate further discussion of the role of different stakeholders in country specific contexts as well as in international fora. It is hoped that this will be debated both as a democratic issue in terms of examining whose interests and concerns get to be represented in policy processes and who has the opportunity to participate in such processes, as well as an epistemological issue in terms of exploring which kinds of knowledge and experiences are regarded as relevant and allowed to influence how society manages alcohol and drug related issues.