Otosclerosis is a disorder causing a hardening of the middle ear bones which leads to a progressive hearing loss. Internationally renowned experts met in Saas Fee (Switzerland) in 2004 to discuss otosclerosis and stapes surgery, and they have subsequently been invited by the editor to present their findings in this publication. From basic to clinical research, all relevant topics such as epidemiology, genetics, histopathology, molecular biology, and virus etiology are described. Also shown are the mechanics of the middle ear in model and in vivo, audiologic and imaging procedures, and surgical techniques including laser surgery. Further papers discuss advantages and disadvantages of stapes prosthesis, stapedectomy versus stapedotomy, and indications and contraindications of common therapies. Finally, postsurgery complications and how to deal with them, short- and long term results, as well as the significance of stapes surgery in training and future developments are presented. This publication will keep the otorhinolaryngologist in clinic and practice up-to-date on current research and clinical development, but also pathologists, radiologists and virologists will find it inspiring reading. <br />