The aim of this book is to bring greater understanding of the centralised enforcement mechanism within the EC Treaty contained within Article 226 EC.1 In doing so, it aims to change the entrenched view of Article 226 as a single function provision within the constitutional architecture of the European Union (EU), to a vision that encapsulates the truly multi-faceted nature of the centralised enforcement provision. The central themes underpinning the discussion of Article 226 are those of legitimacy, transparency, accountability, good governance and good administration. The examination of the policies and management of the enforcement provision is undertaken with reference to a model of administrative legitimacy. This provides the intellectual framework, or lens, through which the central themes are tackled. Enforcement of Member States’ legal obligations under the Treaty is central to the success of the EU. Although the centralised enforcement provisions are by no means the only way by which legal obligations are enforced, they provide the essential top-down mechanism for ensuring that political agreements are transformed into a legal reality. The benefits that citizens derive from adherence to these legal obligations are central to the claims made by EU elites about the legitimacy of the European project as a whole. Domestic politicians and the European institutions continue to try to popularise the EU on the basis that the EU delivers tangible benefits to its citizens. This output legitimacy is now intertwined with an attempt to reform the EU into an organisation that not only delivers tangible benefits to its citizens, but does so using legitimate policy processes that embrace fundamental democratic values: adherence to the rule of law, transparency, participation, accountability and good administration.