 The simple syntactic nature of logical negation belies the profoundly complex and subtle expression of negation in natural language, as expressed in linguistically distinct categories and parts of speech (adverbs, verbs, copulas, quantifiers, affixes). As will be partly explored here (see also Horn 1989, Ladusaw 1996, Pullum 2002), the investigation of the form and meaning of negative expressions in English and other languages and of the interaction of negation with other operators (including multiple iterations of negation itself) is often far from simple, extending to scope ambiguities (Everybody didn’t leave), negative incorporation into quantifiers and adverbs (nobody, never, few), neg-raising (I don’t want to go = “I want not to go”), and the widespread occurrence of negative polarity items (any, ever, lift a finger) whose distribution is subject to principles of syntax, semantics, and pragmatics. At the core of the mental faculty of language, negation interacts in significant ways with principles of morphology, syntax, logical form, and compositional semantics, as well as with processes of language acquisition and sentence processing, whence the prominent role played by work on negation in the development of logic, semantics, linguistic theory, cognition, and psychoanalytic and literary theory.