The central issue in this book is the Europeanization of the principle of legitimate expectations in the context of European administrative law and of the growth of a European ius commune. First, an overview is given of the European principle of legitimate expectations and the equivalent principles in the Netherlands, France and Belgium. Second, the application of the European principles, its spill-over effects and its impact on the principles of legitimate expectations in these national legal orders are examined. The principle of legitimate expectations is one of the many European general principles of law that are applicable whenever a case falls within the scope of European law. The content of the European principle and the criteria for its successful application are described. The principle is applicable in different situations and these are described on the basis of case law (f. ex. transitional measures, revocation). The same procedure is followed regarding the principle of legitimate expectations or equivalent in the Netherlands, France and Belgium. The European principle is stricter than the principles in the Member States because of the severe criterion of a prudent trader and the absolute prohibition of contra legem application. There is a clear influence of the European principle in the situation of the direct application of European law (cases that are fully Europeanized) where authorities and judges have to apply the European principle of legitimate expectations. A national principle that offers broader legal protection can only be applied in cases that are not fully Europeanized (indirect application), as long as it falls within the confines of the European conditions of effectiveness and equivalence (and whereby the European principle is the minimum-standard). The area where the relation and tension between the European and national principles is an important issue is the area of European subsidies and state aid. The Netherlands had to give up a part of the legal protection that it offered on the ...