As a Court based on the rule of law, the Court of Justice of the European Union is guided by that most profound of EU law principles not only when giving rulings on the substance of the cases, but also whenever it takes procedural decisions. However, due to practical necessity, the Court's procedural decisions cannot follow a strictly positivist approach but also take into account other considerations. In order to ensure that due regard is given, in particular, to the principles of legal certainty and equal treatment, the Registry of the Court advises and supports decision-makers. The present chapter seeks to shine a light on that body which might have a somewhat enigmatic flair to it - for outsiders.