The book , suitable for students ( also PHD candidates) and professors of Administrative Law, features a collection of essays that discuss administrative justice systems and their organisation, specifically examining the relationship between Higher and Regional Courts, all from the perspective of ensuring full legal certainty. The selected countries ( Austria, Belgium, France, Italy, Germany, Portugal and Spain) are a useful examples because they include both Unitarian and Federal States. The book offers an interesting overview of the legal systems of countries such as Austria and Portugal, not frequently analysed. Authors: Parisio Vera; Kaschka Jonas; Renders David; Delforge Caroline; Bachini Bruno; Sommermann Karl-peter; Gogos Konstantinos; Alves Correia Jorge; Aguado