The ancient figure of the messenger is re-proposed in this book as the most fitting prototype of a communication in which the media - more than messages and information - are at the center of theoretical attention. Sybille Krämer thus opens a 'third road' between the technical model (inspired by the studies of Friedrich Kittler) and the dialogic model (of Habermasian derivation) and, through the study of some emblematic figures that reveal the hybrid and ambivalent nature of the media, she builds a true and its own phenomenology of mediality. Angels, viruses, money, the translator, the psychoanalyst, the witness: all messengers, third parties who create relationships and mediate between otherwise distinct worlds.