The contributors to this volume provide a critical examination of the notion of bilingualism as it has developed in linguistics and of its use in discourses of social regulation in state and civil society in the twentieth and twenty-first centuries. They attempt to move the field away from a "common sense," but in fact highly ideologized, view of bilingualism as the co-existence of two linguistic systems, and to develop a critical perspective which approaches "bilingualism" as a wide variety of sets of sociolinguistic practices connected to the construction of social difference and of social inequality under specific historical conditions.