In this volume, the editors aim to offer a timely focus on preschool bilingual education in the 21st century by drawing attention to the following trends: (1) the diversity of language models and their hybrid, dynamic and flexible nature; (2) the complexities of children's linguistic backgrounds; (3) children's, parents' and teachers' agencies in interaction; and (4) early bilingual development and education as contextually embedded. Given the complexity of providing a global and comprehensive view of these trends in just one issue, the selection of studies included here seeks to offer insightful consideration of these trends using a range of qualitative and quantitative methods. The contributors explore the trends in different socio-cultural and national contexts in five countries: Finland, Sweden, the Netherlands, Israel and Singapore. The book highlights the need on the one hand to examine early bilingual education within specific socio-cultural contexts, and on the other to search for its universal features. It aims to promote the field of preschool bilingual education as a unique research domain by illustrating its distinctiveness. Last but not least, the studies presented here have a significant contribution to make in the light of the growing interest of policy-makers, ethno-linguistic community leaders, practitioners and researchers in early bilingual development and education. This book was originally published as a special issue of International Journal of Bilingual Education and Bilingualism.