At the height of the protests of the 1960s, video arrives and is immediately swallowed up by artists and activists. It is the right medium at the right time: it creates a “television from below”, one that succeeds in involving the spectator in collective situations, allowing him to consciously and physically enter into the process of transmitting images. From the CCTV installations of Dan Graham and Peter Campus, to the experiments on the electromagnetic signal of Nam June Paik or Steina and Woody Vasulka, to the most innovative Italian experiences (Luciano Giaccari, Alberto Grifi, the Videobase collective, and Laboratorio di Comunicazione Militante), Simonetta Fadda's book analyses video as a technology, and as a cultural form of the analogue era, tracing its initial history in the world of art and political activism, up to 1979. Published for the first time in 1999, in this new edition, extensively updated and supplemented with new material and writings by the "pioneers" of video art in Italy, Definizione Zero extends the horizon of research to the visual turn brought about by the digital, with a final reflection on the aesthetic and anthropological fallout of digital technology.