Over the past decades, the forms of private actors' involvement in politics and policy-making have multiplied at all levels of government and across policy areas. At the same time, expert groups, multi-stakeholder fora, public-private partnerships , direct and indirect lobbying campaigns, and the outsourcing of public services have all become the focus of scholarly attention across national and transnational contexts. This special issue aims to contribute to our understanding of the forms that this involvement of private actors in politics and policy-making has taken and of the processes leading to the establishment of such forms of cooperation. This issue’s contribution lies in its bringing together five case studies focusing on modes of public-private interaction that go beyond the frequent focus on the lobbying of decision-makers by special interests. Their approaches share three important features: the originality of their objects of analysis; their use of less frequent theoretical frameworks for conceptualising public/private interactions; and their careful restitution of the historical and political contingency of the public/private interactions that the authors analyse.