From biology to genetics, from medicine to astronomy, the camera reveals an invisible world to science. The first image of a black hole fifty-five million light years away is the plain confirmation of Einstein’s theory of relativity and, for all of us, the moving realisation that the medium shows us not only the world but the infinite universe. If it certifies the existence of stars and planets, it also gives bacteria, viruses and cells a portrait of brilliant forms and colours, makes visible the trajectories and the behaviour of invisible objects, and follows the line of progress and research as far as optogenetics. Between the end of the nineteenth century and the beginning of the twentieth, great scientific and technological development met the invention of the medium, laying the deep roots of an indissoluble partnership. In Paris in 1895 the German physicist Wilhelm Röntgen discovered X-rays by chance and made the first radiograph in history, fixing the hand of his wife. From that moment science and the image began their path of dialogue, support and confrontation in every field.