Determining the authorship and originality of artistic works is a key element essential for fully enjoying the art and for the correct functioning of the market and many cultural centres. It is one of the tasks falling upon institutions and different categories of people from artists’ foundations to museums, public administrations, academics, gallery owners and art collectors… All those concerned by it encounter many problems when conducting the task. This book, derived from an international seminar organised by the Gala-Salvador Dalí Foundation diffuses the knowledge, experience and opinions of some of the most prestigious experts on these subjects. Furthermore, it provides some new angles, proposals and linguistic elements that can help to understand the difficulties presented by the topic and to improve its legal regulation. Lluís Peñuelas has been the General Secretary of the Gala-Salvador Dalí Foundation from 1990 to date. He is responsible for managing the Foundation’s four museums and their general administration.