Kooiman in his chapter presents the foundations of his approach to interactive governance and governability, and the way it has been used and developed in empirical research. In this chapter interactive governance is defined as the whole range of interactions to solve societal problems and to create societal opportunities, the formulation and application of principles guiding those interactions and the care for institutions enabling them. Governability is seen as the overall quality for governance of any societal entity, divided into a system-to-be-governed, a governing system and a system of interactions mediating between the two. Diversity, complexity, dynamics and scale are argued to be major variables influencing the governance and governability of societal entities. In such governance the state, market and civil society play roles; Kooiman argues that these should be analysed at both an actor and a structural level.