The Dossier “Essential Notions in Visual Arts” presents, in a set of articles, the questioning of the fundamental notions that delimit the field of Visual Arts. It is understood that they have been constantly reexamined and the main reason for this is the experimental character of the artistic making and the adoption of original procedures and ways of thinking, challenging the very definition of a work of art. A whole repertoire of notions, and the relations between them, constitute the constellation that establishes art as a field of knowledge.