This review summarizes the anatomy, cellular physiology, neural pathways and central processing of the auditory system. Peripheral structures (outer, middle and inner ear), mechanoelectrical transduction by hair cells, cochlear mechanics and frequency mapping are described. Ascending auditory pathways from the cochlear nerve through brainstem nuclei to the auditory cortex are outlined, including parallel processing of timing and intensity cues. Clinical aspects such as hearing loss types, diagnostic methods (audiometry, otoacoustic emissions, auditory brainstem responses), and current therapeutic and rehabilitative approaches (hearing aids, cochlear implants, pharmacological and gene therapies) are discussed. Emerging directions in auditory neuroscience, including hair cell regeneration, optogenetic stimulation and brain–computer auditory interfaces, are highlighted.