The (sub)principles of effectiveness is rather new for many lawyers. This novelty is partly because these principles are related not only to law from a more classical perspective but also to academic fields like social sciences and economics. Modern textbooks on administrative law are sometimes split into two parts: one part on administration and law and another part on law and administration. The first part is, from an administrative law perspective, the most innovative. It is mainly focused on policy, constitutional, and organizing aspects of the administration. The approach is contextual, and it draws on different disciplines. It deals with administrative developments, centralized and decentralized administration, the different types of administration, the management aspects of administration, the development of agencies, the different methods of internal and external coordination, and the position of the key players in the field of the administration. The second part concerns the analysis of the principles of judicial review as they have been developed by the courts, the ombudsman, and other controlling institutions. These principles are applied to control and structure the administration. It also takes full account of the legislative and political initiatives that are relevant for the development of administrative law, including the role played by the different powers in the state. In this chapter, we integrate these two parts of ‘administration and law’ and their corresponding approaches. This reflects the interdisciplinary nature of the development of the principles in general and more specifically in the (sub)principles of effectiveness. These principles can also be applied mutatis mutandis in other contexts that restrict the perspective of the administration in a narrow sense, like the administrative court and the fourth power institutions.