How can genetics be useful to general otorhinolaryngologists and their patients? This book summarizes the most recent information on genetic diseases, including deafness and head-and-neck cancer, that is relevant to clinical practice, particularly with reference to accurate genetic counseling. The first part of the volume presents a basic and general review of genetics. Up-to-date information on deafness genes is given and the mouse model for hearing impairment is thoroughly described. The application of molecular analysis of head-and-neck carcinoma has been one of the fundamental breakthroughs in understanding the cell biology of the carcinoma. Two chapters are devoted to the discussion of tumor suppressor genes and oncogenes. This book is highly recommended since genetics, particularly molecular genetics, is still an unfamiliar subject to otorhinolaryngologists. Yet there is a constant need to be alert to the possibility of diagnosing hereditary disorders.