In the past five years, interest in the linguistic role of optimality has been sparked by the sharpened notions of "economy" in Chomsky's Minimalist Program and by Prince and Smolensky's Optimality Theory, originally developed for phonology. Work on these ideas has raised many new questions. These include new versions of an old debate between constraints on derivations and constraints on representations and entirely new questions about the nature of the candidate set, as well as questions about learnability and computability. Writing from a broad range of empirical and theoretical perspectives, the contributors to this volume examine the role of competition in syntax and in syntactic interfaces with semantics, phonology, and pragmatics, as well as implications for language acquisition and processing.