This book is a companion volume to the authors' Phonetics for Communication Disorders; and, just as that text aimed to introduce all the relevant areas of phonetics to the student and practitioner of speech-language pathology, so this book aims to describe those approaches to phonology that the authors have deemed most relevant to communication disorders. This book examines schools of thought in theoretical phonology, and their relevance to description, explanation and remediation in the clinical context. A recurring theme throughout the book is the distinction between phonological theories that attempt elegant, parsimonious descriptions of phonological data, and those that attempt to provide a psycholinguistic model of speech production and perception. Clearly, if we are confronted with speech data from a highly unintelligible client, then an analysis that sorts the data into clear patterns will be extremely useful. Such an analysis may not explain why such patterns arose, or how best to remediate them. Analyses derived from more phonetically concrete or psycholinguistically valid phonologies may well provide just that extra information.