Understanding phonology is intended as an introductory textbook in phonology for students with little or no prior knowledge of linguistics.The book served as the main text in both an introductory course to phonology for graduate students in linguistics as well as one for undergraduates at Ohio State University. Input from students in these classes regarding aspects of the book contributed to our evaluation in this review. We are particularly grateful to the following students for their helpful comments: Sharonne Albicker, Ryan Ginstrom, Jette Hansen, Sun-Hee Lee, Mary Paster, Shravan Vasishth, Jinyi Wang and Peggy Wong. We would also like to thank Carlos Gussenhoven, Sharon Hargus, Robert Levine and David Odden for valuable comments on a draft version of this review. The goal of the text, as stated, is to provide an introduction to all major topics in phonology, and a comprehensive survey of phonological theory. The book aims to explain the basics of phonology, rather than arguing for a particular theoretical position, thereby giving students a sound understanding of the field.