This book is as much about phonological theory as about the phonology of English. It is primarily designed as a university-level text for use on intermediate and advanced courses, but it will be of value to anyone interested in recent theoretical developments in the field. The book is virtually unique among theoretical treatments of English phonology in drawing on material from a wide range of dialects. This orientation derives from the view that phonological differences between grammars, no less than syntactic differences, are constrained by universal principles and occur within fixed bounds defined by a small number of parameters. Against this background, this book analyses a wide range of variables in English which offer revealing insights into the limits of phonological variation. The reader is introduced to recent innovations in non-linear theory, particularly those concerning the internal composition of segments and their organization in constituent structure. Phenomena discussed include vowel length, syllabic structure, stress, consonantal weakening and vowel reduction and syncope.