This volume aims to extend both the range of analyses and the database on nominal classification systems. Previous analyses of nominal classification systems have focussed on two areas: the semantics of the classification system and the role of the system in discourse. In many nominal classification systems, there appear to be a significant percentage of nominals with an arbitrary classification. There is a considerable body of literature aimed at elucidating the semantic bases of clasification in such systems, thereby reducing the degree of apparent arbitrariness. Contributors to this volume continue this line of enquiry, but also propose that arbitrariness in itself has a role from a wider socio-cultural perspective. Previous analyses of the discourse role of classification systems posit that they play a significant role in referential tracking. For the languages surveyed in this volume, contributors propose that reference instantiation is an equally significant function, and indeed that reference instantiation and tracking cannot be properly divided from one another. This volume provides detailed information on classification in a number of northern Australian languages, whose systems are otherwise poorly known.