Restoring hearing to the deaf. Miracle? Science fiction? Magic? No: reality and technology, which for over forty years have radically changed the lives of hundreds of thousands of people. We are talking about the cochlear implant, a biomedical device that can be implanted in the cochlea (a region of the skull) and that stimulates the neurons of the auditory nerve, allowing for the reconstruction of compromised sound perception in people with sensorineural deafness.