This volume is one in a series of monographs being issued under the general title of "Disorders of Human Communication". Each monograph deals in detail with a particular aspect of vocal communication and its disorders, and is written by internationally distinguished experts. Therefore, the series will provide an authoritative source of up-to-date scientific and clinical informa- tion relating to the whole field of normal and abnormal speech communication, and as such will succeed the earlier monumental work "Handbuch der Stimm- und Sprachheilkunde" by R. Luchsinger and G. E. Arnold (last...