This is a comprehensive introduction to theoretical linguistics. It presupposes no previous knowledge and terms are defined as they are introduced; but it gives a rigorous and technical treatment of a wide range of topics, and brings the reader to an advanced level of understanding. Since its first publication in 1968 Introduction to Theoretical Linguistics has been one of the classic introductions to the discipline. In a field which is often seen as rapidly moving, it will continue to be used by students seeking an overview of the central areas of linguistics - phonetics and phonology, grammar and semantics - and to be of great value to anyone interested in the ways in which theory can help to explain the key problems of human language.