This study has a dual orientation and a dual aim: Theoretical and analytical. On the theoretical side, it presents a relatively little know cognitive model of categorization, Vantage Theory, surveys its linguistic applications and proposes its adaptation, called Extended Vantage Theory. In the analytical part, the adaptation serves a specific purpose: an account of the use of the English articles. The book is thus as much a testing ground for a theory as it is a hands-on struggle with specific data.