Alessandra Giorgi and Giuseppe Longobardi's important study of the argument structure of lexical projections, in particular of noun phrases, makes substantial advances in this relatively neglected area. Working within a Government and Binding framework, the authors present strong new arguments in favor of the existence of empty categories, and evidence for the correct understanding of word order parameters and of Chomsky's Projection Principle. In particular, they elaborate and discuss a number of tests intended to define under which lexical and syntactic conditions an empty prenominal subject may or must occur in a noun phrase. The levels of structural attachment of the arguments of a head noun are carefully established by supporting assumptions made in this domain with independent evidence. As well as its theoretical advances, this book provides a descriptive analysis of nominal structure in Romance languages, compares it with corresponding structure in Germanic languages, and offers an introduction to Italian phrase structure.