Throughout his extensive trajectory Antoni Tàpies engaged in an unceasing inquiry into different realms of creation – painting, sculpture, graphic works and writing – thus forming a singular identity whose projection and influence made him a referent for subsequent generations of artists. From his initial figuration in late Surrealist style he would move in the late 1950s to the creation of highly material works. In these pieces Tàpies manipulates the density of the support medium with incisions, chipping, graffiti and collages, treating it as an open space, as if it were a wall. Physical presence, such as that materialized in Superposition de matière grise (Superimposition of Grey Matter), distinguishes this canvas-wall from the Western tradition of canvas-window. The experimentation shown by this work in this regard is an important step towards his later conjugation of other materials, textures, signs, objects and ordinary motifs that heighten the presence of the real and reflect the artist’s interest in the physical transformation of the elements. The works by Tàpies in the Museo Reina Sofía collection give a clear idea of the different stages of his oeuvre, which offers a reflection on the nature of images, expressed in a complex language of symbolic origin and a constant vindication of material.