<P>Over the past two decades, Ray Jackendoff has persistently tackled difficult issuesin the theory of mind and related theories of cognitive processing. Chief among his contributions isa formal theory that elaborates the nature of language and its relationship to a broad set of otherdomains.</P><P>Languages of the Mind provides convenient access to Jackendoff's workover the past five years on the nature of mental representations in a variety of cognitive domains,in the context of a detailed theory of the level of conceptual structure developed in his earlierbooks <I>Semantics and Cognition</I> and <I>Consciousness and the ComputationalMind</I>. The first two chapters summarize the theory of levels of mental representation("languages of the mind") and their relationships to each other and show how conceptual structurecan be approached along lines familiar from syntactic and phonological theory. From this background,subsequent chapters develop issues in word learning (and its pertinence to the Piaget-Chomskydebate) and the relation of conceptual structure to the understanding of physicalspace.</P><P>Further chapters apply the theory to domains outside of traditionalcognitive science. They include an approach to social and cultural cognition modeled on firstprinciples of linguistic theory, the beginnings of a formal description of psychodynamic phenomena,and a discussion of musical parsing and its relation to musical affect that bears on currentdisputes in linguistic parsing. The final chapter takes up a long-standing conflict betweenphilosophical and psychological approaches to the study of mind, arguing that mental representationsshould be regarded purely in terms of the combinatorial organization of brain states, and that thephilosophical insistence on the intentionality of mental states should beabandoned.</P><P>Ray Jackendoff is Professor of Linguistics at BrandeisUniversity.</P>