A decade of innovative findings in the research of molecular biology of hearing and deafness is reflected in this volume. The genetic causes for many types of syndromic and non-syndromic deafness are identified and genotypic-phenotypic relationships are explored. Although the type and degree of deafness caused by mutations in different genes significantly overlap, relatively unique age-related audiometric profiles are also emerging. For example, the audioprofile of DFNA1 and DFNA6-14 is a low-frequency sensorineural hearing loss; with DFNA8-14 it is a mid-frequency sensorineural hearing loss, and with DFNA2, DFNA5 and DFNA20-26 it is a high-frequency progressive hearing loss. Recognizing such audioprofiles can facilitate well-guided decision-making in clinical practice and can direct genetic testing for deafness. With an accurate genetic diagnosis, prognostic information can be provided to patients and their families.