The topic of this book is the notion of `focus' and its linguistic characterization. The main thesis is that focus has a uniform grammatical identification only as a syntactic element with - in English at least - a certain systematic phonological interpretation and - presumably universally - a range of semantic interpretations. In broad respects, the framework within this investigation is conducted is that of Chomsky & Lasnik (1977) and the subsequent Government and Binding framework. After considering defining the location of prominence in a focused phrase in terms of constituent structure, the author argues that an argument structure approach to the focus phrase/prominence relation is more promising. This is then exemplified in analyses of cleft focus and constructional focus.