In this Urban Corporis volume, ?The city and the skin?, we asked the authors to read, define and interpret the role of the skin as a facade, as a protection, as a compositional image of urban revelation. Without formal restrictions, without ethical preconceptions: the skin as part of the building designed to mediate the relationship. The architectural skin, understood as the technological system of delimitation between architectural space and unbuilt environment, can be analyzed as a boundary system between interior and exterior, the most evident expression of the identity of an artifact. In this dual role of border and interface, receptive as active, the skin of an architecture (seen also through art) is charged with a double value: an element of covering and protection and, at the same time, a tool of relationship and interface, in fact, towards the external world.