Alexandra Y. Aikhenvald is Professor and Associate Director of the Research Centre for Linguistic Typology at La Trobe University. She has worked on descriptive and historical aspects of Berber languages and published, in Russian, a grammar of Modern Hebrew (1990). She is a major authority on typological and areal features of South American languages, particularly of the Arawak family: Bare (1995, based on work with the last speaker, who has since died), Warekena (1998), and Tariana (2003). Her monographs include Classifiers: a Typology of Noun Categorization Devices (2000, 2003), Language Contact in Amazonia (2002), Evidentiality (2004), and The Manambu Language of East Sepik, Papua New Guinea (2008). R.M.W. Dixon is Professor and Director of the Research Centre for Linguistic Typology at La Trobe University. He has published grammars of a number of Australian languages (including Dyirbal and Yidiñ), in addition to A Grammar of Boumaa Fijian (1988), The Jarawara Language of Southern Amazonia (2004) and A Semantic Approach to English Grammar (2005). His works on typological theory include Where have All the Adjectives Gone? and Other Essays (1982) and Ergativity (1994). His essay The Rise and Fall of Languages (1997) expounded a punctuated equilibrium model for language development which is the basis for his detailed case study Australian Languages: their Nature and Development (2002). He is currently working on an extensive study of the basic linguistic theory.