This monograph is devoted to a description and demonstration of modern diagnostic technic as bearing on the upper air-passages. The author finds warrant for such a monograph in the recent important additions made to such diagnostic procedures. This technic is becoming more and more highly specialized, and is demanding much study and experience. Naturally the subjects of greatest interest are those of direct laryngoscopy, bronchoscopy and esophagoscopy. Various methods and instruments employed in these procedures are not only described, but also excellently illustrated. The monograph constitutes a clearly presented and well-illustrated brief account of all diagnostic procedures relating to the upper air-passages.