Hearsay or indirect testimony receives little discussion even today in epistemology, and yet it represents one of the cardinal modes for the transmission of knowledge and for human cognitive development. It suffices to think of school education whereby a student listens to teachers reporting knowledge acquired, often indirectly, from the most varied sources such as text books, newspapers, personal memory, television, etc… Or let us consider the importance of oral tradition in the social and cultural development of civilisations. Or even let us call to mind the learning process of infants who, only thanks to the knowledge learned from others, succeed in learning the language. Finally, with the emerging digital technology, the information gleaned from third parties is influencing the creation of knowledge in a full gamut of fields, in a quasi-comprehensive manner. This leads us to claim that hearsay, despite the reductionist conceptual scheme to which epistemology has confined it in that indirect testimony, is in any case quintessential in the dissemination of knowledge. This work fully expounds upon the basic mechanism of indirect testimonial transmission and provides an epistemologically founded explanation of the cognitive possibilities of hearsay by investigating, in the light of the anti-reductionist paradigm, three mutually connected epistemic properties, namely trust, reputation and coherence, that are key in the epistemic justification of the truth acquired via an indirect testimony.