Book excerpt: The Handbook of Speech and Language Disorders presents a comprehensive survey of the latest research in communication disorders. Contributions from leading experts explore current issues, landmark studies, and the main topics in the field, and include relevant information on analytical methods and assessment. A series of foundational chapters covers a variety of important general principles irrespective of specific disorders. These chapters focus on such topics as classification, diversity considerations, intelligibility, the impact of genetic syndromes, and principles of assessment and intervention. Other chapters cover a wide range of language, speech, and cognitive/intellectual disorders.