Languages of the Mind provides convenient access to Ray Jackendoff's work 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 earlier books. The first two chapters summarize the theory of levels of mental representation ("language of the mind") and their relationships to each other and show how conceptual structure can 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-Chomsky debate) and the relation of conceptual structure to the understanding of physical space.