Communication disabilities are common, although their precise nature and degree of severity vary greatly among individuals. They are among the most handicapping of disabilities because they isolate a person and in so doing restrict social, educational, and occupational opportunities. One of the purposes of this book was to bring together theoretical, practical, and clinical knowledge from several disciplines that bear on language and communication into some reasonably accessible form. The intent is to provide a broad and multi-faceted view of language development and language disorders. Thus, contributions from education, linguistics, psychology, pediatrics, psychiatry, neurology, neuropsychology, and speech therapy are included. They describe our current knowledge of language development, suggest classifications for language pathology, outline what is known of the epidemiology of language difficulties, consider assessment and therapy, alternative communication systems and the impact of the new technology on communication aids. The variety of perspectives that it provides will make it particularly useful to the range of specialists who are concerned with the development of communication skills and language disorders.