Book excerpt: This book systematically discusses the pathogenesis, prevention, and the current and potential clinical treatment of hearing loss, as well as the latest advances in hearing research. Hearing loss is a prevalent sensory disorder, which according to a 2015 World Health Organization (WHO) report affected 9% of the global population in 2015. As populations continue to age, more and more people are suffering from the condition, with 60% of those aged between 65 and 75 affected. Hearing loss seriously affects patients’ ability to work ability and quality of life, and as such deafness has become an increasingly urgent social problem around the globe. Sensorineural hearing loss is mainly caused by damage to the hair cells (HCs), and the subsequent loss of spiral ganglion neurons (SGNs). Damage to the HCs in the inner ear can result from exposure to loud noises and environmental and chemical toxins as well as genetic disorders, aging, and certain medications. This book provides ENT specialists and researchers, as well as individuals affected a comprehensive introduction to the field of hearing loss.