The normal anatomy and physiology of the external auditory canal is covered, followed by detailed descriptions of disorders and treatments of known and unknown etiology. Included are asteatosis, bacterial and fungal external otitis, bullous myringitis, allergic dermatitis, keratosis obturans, canal cholesteatoma, exostosis, osteoma, ceruminoma, basal and squamous cell carcinoma, and adenoma. A review of malignant external otitis is included with special emphasis on the expanding role of outpatient treatment and the use of oral antimicrobials.