Basic and clinical investigations of the hearing mechanisms in vertebrates are to be conducted by a multidisciplinary consortium of researchers from the Massachusetts Eye and Ear Infirmary, Massachusetts Institute of Technology, Harvard Medical School, and Massachusetts General Hospital. Studies of middle- and inner-ear mechanics, sensory transduction, and neural activity are performed on lizards, cats, and humans. The principal approaches are electro-physiological and anatomical in orientation. The clinically related research closely follows concepts developed from basic studies and are motivated by a need to understand the nature of the disorders so that diagnostic techniques and suggested treatments have a rational basis.