This book sets out with the highly ambitious aim of combining two fields of investigation which are not self-evidently relatable - namely, on the one hand, research into dynamic systems and, on the other, research into multilingualism. It seeks to use notions of dynamic systems as they have been applied in such areas as physics and meteorology as the basis for the development of a dynamic model of multilingualism. The writing is clear and the argumentation cogent throughout, and although the text is certainly not an easy read, its insightfulness fully repays the close attention it demands. There is absolutely no doubt that this volume will quickly become - and will deserve to become - an indispensable reference-point in any discussion of multilingualism. David Singleton, Associate rofessor of Applied Linguistics, Trinity College, Dublin, Ireland.The model presented in this volume draws together various strands of research - second language acquisition theory, bilingualism research, dynamic systems theory - to develop a novel approach to this challenging subject. Its main focus lies on the psycholinguistic dynamics of multilingualism, the processes of change in time affecting two or more language systems.