The Generative Lexicon presents a novel and exciting theory of lexical semantics that addresses the problem of the "multiplicity of word meaning" - that is, how we are able to give an infinite number of senses to words with finite means. The first formally elaborated theory of a generative approach to word meaning, it lays the foundation for an implemented computational treatment of word meaning that connects explicitly to a compositional semantics. In contrast to the static view of word meaning (where each word is characterized by a predetermined number of word senses) that imposes a tremendous bottleneck on the performance capability of any natural language processing system, Pustejovsky proposes that the lexicon becomes an active - and centralcomponent in the linguistic description. The essence of his theory is that the lexicon functions generatively, first by providing a rich and expressive vocabulary for characterizing lexical information; then, by developing a framework for manipulating fine-grained distinctions in word descriptions; and finally, by formalizing a set of mechanisms for specialized composition of aspects of such descriptions of words, as they occur in context, extended and novel senses are generated. The subjects covered include semantics of nominals (figure/ground nominals, relational nominals, and other event nominals); the semantics of causation (in particular, how causation is lexicalized in language, including causative/unaccusatives, aspectual predicates, experiencer predicates, and modal causatives); how semantic types constrain syntactic expression (such as the behavior of type shifting and type coercion operations); a formal treatment of event semanticswith subevents); and a general treatment of the problem of polysemy.