Designed to acquaint the reader with the field of phonology -- the study of the systems of linguistically significant sounds -- this book begins with a brief introduction to linguistics and a discussion of phonology's place within that field. It then goes on to cover a variety of topics including the nature of phonological units, phonological rules, which types of phenomena interest phonologists, and the evolution of phonological theory. Suitable for many applications, this volume assumes no previous knowledge of linguistics. An excellent text for use in first or second year phonology courses, it will also be of value to those involved in cognitive science, neuroscience, artificial intelligence and computer science.