Optimality theory has revolutionized phonological theory, and its insights are now being applied to other central aspects of language. With contributors that include the leading researchers in the field, this book presents the fruits of the research as applied to syntax and to language acquisition, as well as considering the main lines of attack on OT by rule-based grammarians.This book is intended for a broad range of linguists at graduate level and above, including students, academics, and researchers.