This volume provides a comprehensive account of the implementation of bilingual education programmes in countries throughout the world. Bilingual programmes have been implemented to achieve a variety of educational and social goals in different contexts. Some programmes are intended to support the maintenance of national minority languages or to revitalize languages whose long-term survival is threatened; others aim to help recent immigrants succeed academically while making the transition to instruction taught primarily through the majority language of the society. In addition, bilingual programmes have been used to teach additional languages to students from the majority or dominant language group. Similar theoretical principles underlie the development of bilingual conversational and academic skills in all these diverse contexts.