The book before carries a broad title. In the Dutch literature, the terms lawfinding and lawmaking are often used interchangeably. From a legal point of view, however, it makes quite a difference to the position of the court whether lawfinding or lawmaking is meant. Why write a book about lawmaking by the courts just in the area of administrative law? In administrative law, the administration is positioned between the legislature and the judiciary. The courts review decisions taken by the administration in implementing the law; however, where the administration has often been granted a degree of discretion, the courts access the lawfulness of the decision. The relation administration-judiciary raises so many specific questions that it justifies a book on judicial lawmaking in administrative matters. The authors are all members of the research program Public Law of the Ius Commune School.