Biliteracy - the use of two or more languages in and around writing - an increasingly inescapable feature of our lives and schools worldwide, yet one which most educational policy and practice continues blithely to ignore. The continua of biliteracy featured in the present volume offers a comprehensive yet flexible model to guide educators, researchers and policy-makers in designing, carrying out and evaluating educational programmes for the development of bilingual and multilingual learners, each programme adapted to its own specific context, media and contents. The continua model is premised on a view of multilingualism as a resource and on the metaphor of ecology of language.