Misrepresentation and Misappropriation. In: Ohly A. (Red.) Common Principles of European Intellectual Property Law. Tübingen: Mohr Siebeck. p. 247-254. In this article it is submitted that misrepresentation and misappropriation are the two most important common principles, or common ‘basic moral feelings’ of intellectual property and unfair competition law in Europe and elsewhere. It is also fully acknowledged that free trade, free speech, anti-trust law, legal certainty and the general need to be able to use and take advantage of existing work and ingenuity of others, are vital countervailing principles which determine the very important limitations and exceptions in intellectual property and unfair competition law to a large extend. These vital countervailing principles, however, are not discussed here. “The prophecies of what the courts will do in fact, and nothing more pretentious, are what I mean by the law.“ (Oliver Wendel Holmes) The difference between legal academics on the one hand and judges and legal advisors on the other, is that the latter actually have to decide cases or predict what these decisions are likely to be or going to be. In order to make decisions all people (including judges) ultimately need some kind of emotional conviction that they should make a particular choice. A feeling that in a certain case a certain decision is preferable. Without such a feeling a person cannot decide anything. In fact, it has been proven that people with a particular kind of brain damage which blocks their emotional mental capacities cannot decide anything: they keep on weighing different possibilities against one another, without being able to decide. (Damasio). Thus, anyone who has to decide anything, including judges, ultimately needs some kind of feeling of emotional conviction that makes them decide. Therefore, in this essay, the phrase ‘common principles’ is sometimes used interchangeably with common ‘basic moral feelings’ of intellectual property, because the author is convinced that there is an important moral-emotional side to rules and decisions in intellectual property law. Misrepresentation and Misappropriation. In: Ohly A. (Red.) Common Principles of European Intellectual Property Law. Tübingen: Mohr Siebeck. p. 247-254.