This article aims to provide a fairly succinct, practical analysis of the way in which the Court of Justice of the European Communities (the “supreme court” for all questions of interpretation arising under the EEC, ECSC and Euratom Treaties) has developed one particular fundamental principle of Community law, the doctrine of “legitimate expectations”. The emphasis throughout is not only on the exact legal formulation of the doctrine, but also on whether or not the doctrine can be said to match up to expectations that, economically, might be regarded as “legitimate”. Before embarking on the substance, it may be useful to set out briefly, for those who are perhaps unfamiliar with the way in which the judicial machinery of the European Community operates, a description of how cases in which this principle has been pleaded come to arise and how they reach the Court.