First published in 1988, this book is concerned with the definite and indefinite articles in English. It provides an integrated pragmatic-semantic theory of definite and indefinite reference, on the basis of which, many co-occurance restrictions between articles and non-modifiers are explained. At the general theoretical level, this book looks at the role of semantics in the prediction of all and only the grammatical sentences of a language. A generalisation is proposed uniting semantic oppositions underlying ungrammaticality with syntactic oppositions between conditions of application on transformational generative rules. A procedure is suggested for distinguishing semantic from syntactic causes of ungrammaticality. At a more particular level, the book explores the nature of reference. It examines an important selection of subjects such as the contrast between definiteness and indefiniteness, the relationship between definite and demonstrative reference, and the relationship between pragmatic and logical aspects of determining meaning.