This dissertation is an attempt to study the legal and non-legal aspects of the issues arising from the authentication of a work of art. It was motivated by the question of how a work of art can be authenticated under the current system of authentication. Since various components are involved in the current system of authentication, this dissertation discusses some circumstances under which art authentication issues arise with special focus on the art expert’s opinion, be it an opinion of a scholar, a dealer, a curator or a member of an Authentication Board or Committee. By exploring the art historical and scientific tools for determining authenticity, this dissertation attempts to clarify the reason why greater weighting is given by the art market and the courts of law to one or another method (art historical or scientific) depending on the circumstances. Yet, the main objective of this dissertation is to ascertain whether art experts face potential risk of legal liability for rendering an opinion on the authenticity of a work of art. It does so by examining some of the causes of action most usually brought against art experts under Common law. I am far from concluding that the fear of art expert in terms of possible legal liability is absolutely justifiable.