Colin Baker is Emeritus Professor at Bangor University, UK. He is the author of over 140 research publications, a best-selling book for parents of bilingual children and an encyclopedia, all on the subject of bilingualism, as well as the six previous editions of this textbook. He is the former co-editor of the Bilingual Education and Bilingualism book series for Multilingual Matters and was editor of the International Journal of Bilingualism and Bilingual Education for 15 years.Wayne E. Wright is Professor and Barbara I. Cook Chair of Literacy and Language, Purdue University, USA. He has published extensively on bilingual education and bilingualism, and is the co-editor of the Journal of Language, Identity, and Education and the Bilingual Education and Bilingualism book series for Multilingual Matters.