Underlying the apparent diversity shown by the thousands of mutually incomprehensible languages of the world, there is a remarkable, elegant and principled unity in the way that these languages exploit the phonetic resources of speech. It is these principles that Professor Laver sets out to describe in this major new textbook. Assuming no previous knowledge of the subject, it is designed for readers who wish to pursue the study of phonetics from an initial to an advanced stage, equipping them with the necessary foundations for independent research. The classificatory model proposed unifies the description of linguistic, paralinguistic and certain extralinguistic aspects of speech production. The book moves from a presentation of general concepts to a total of eleven chapters on phonetic classification, and it includes discussion of other issues such as the relationship between phonetics and phonology, the nature of accent, dialect and language, and the description of voice quality and tone of voice. Every descriptive category is illustrated by words in phonetic transcription, from over 500 of the world's languages. Principles of phonetics will be required reading and an invaluable resource for all serious students and scholars of speech and language.