The objective of this book is to introduce the cochlear implants: from principles to practice. A cochlear implant is a surgically implanted electronic device that provides a sense of sound to a person who has a severe or profound hearing loss. A cochlear implant does not cure deafness or hearing impairment, but is a prosthetic substitute which directly stimulates the cochlea. This book comprised of five sections that include aspects of hearing loss, assessment of cochlear implant candidacy, the cochlear implant/surgical procedures, results and outcomes of cochlear implantation, and current concepts and future technology, which are further divided into 22 chapters. This book provides an in-depth discussion on prosthetic restoration of hearing via implantation. The text succinctly discusses the scientific principles behind cochlear implants, examines the latest technology, and offers practical advice on how to assess candidates, how to implant the devices, and what rehabilitation is most effective.