The purposes of this seminar are twofold. First, according to mainstream comparative analysis, it will show how legal systems – at least in countries that have attained a certain degree of economic development – face similar problems and achieve similar results with the help of different legal instruments and doctrines. Examples will be provided, such as the treatment of gifts and the gratuitous expenditure of labour or the gratuitous user of someone else’s assets and the treatment of loss of chance and pure economic loss. The fluidity of borders between contract, restitution, tort and property will be pointed out with the help of paradigmatic cases such as restitutionary damages or disgorgement of profits. This mainstream convergence thesis does not hold true, however, in several areas of Private Law where differences among national legal systems in the EU are significant. Those differences concerning, for example, pre-contractual duties to inform and the avoidance of contracts for mistake and deceit, will be examined. The seminar’s second purpose is to focus on some examples of the influence of EU Law in Private Law. EU Law has proved to be one of the most influential factors in the development of the Private Law of the Member States, both at the level of substantive and choice-of-law rules. Again examples will be provided respectively of this influence of primary and secondary EU Law namely, in Private International Law, on the selection of the relevant connecting factors to determine the law applicable to both legal and natural persons and, regarding secondary European legislation, in some of the fields, particularly in contract law, where this influence has been more pervasive: individual labour contracts, life insurance and the regime of self-employed commercial agents.