For this Ninth Edition, the name of Dr. John Jacob Ballenger appears as a junior author. Considerable revision has been made in special chapters by Dr. J. D. Kelly in describing his technique of arytenoidectomy. Chapters by Dr. Alfred Lewy on "Physiology and Functional Tests of the Labyrinth" and "Inflammatory Diseases of the Labyrinth" and by Drs. Gabriel Tucker and C. L. Jackson on "Peroral Endoscopy" have been extensively revised. There is a great deal of information for reference by pediatricians in this book.