Public and stakeholder participation in public environmental decision-making is widely assumed to foster effective governance and secure environmental benefits. Participation is almost never a strict necessity. Even where it is legally mandated to some degree, there remains substantial leeway for decision-makers in terms of exactly how to design and execute a participatory process. Participation is therefore a deliberate choice made by public managers. Participatory water management planning under the European Water Framework Directive (WFD) provides a particularly apt setting to research the link between participation and environmental outcomes. Sustainable water governance itself is a policy field of major importance, which has incorporated collaborative approaches from early on. The WFD explicitly mandates participation in the course of its implementation. This introduction presents an overview of the key concepts covered in the subsequent chapters of this book. The book states that in contrast to cases of public protest or public mediation processes, the WFD only seldom makes headline news.