Cochlear implants are the first devices to successfully restore neural function. They have instigated a popular but controversial revolution in the treatment of deafness, and they serve as a model for research in neuroscience and biomedical engineering. After a visual tour of the physiology of natural hearing the function of cochlear implants will be described in the context of electrical engineering, psychophysics, clinical evaluation, and my own personal experience. The audience will have the opportunity to experience speech and music heard through a cochlear implant. The social implications of cochlear implantation and the future outlook for auditory prostheses will also be discussed.