The study of bilingualism - the subject of this important textbook - is no longer exclusively an academic preoccupation but is a practical necessity in today's multilingual world. Over the past decades, researchers from a wide range of disciplines - linguistics, psychology, neurology and sociology - have been fragmented and often inaccessible to students. Bilinguality and Bilingualism (a thoroughly revised and updated version of the authors' textbook published in French) provides a comprehensive, critical review of current research, focusing on the need for genuinely explanatory accounts and the development of satisfactory theoretical models. The book explores the way in which bilingualism develops in childhood or later, on its social, neurological and psychological foundations, and on the social and cultural consequences of bilingualism. It also explores the wider issues of languages in contact; both psycholinguistic research to language teaching, translation and interpreting, and also language planning and policy-making. The multidisciplinary material is deftly and logically organised to provide a refreshingly clear synthesis which will be invaluable to students and also to specialists who want an up-to-date account of research in different disciplines. It will also be an important reference work for language teachers and for professionals involved in language planning and multilingual education.