This book is designed to provide practical applications of sociocultural theory with regard to teachers'roles in second language education. By providing specific examples of teachers' roles in the classroom,the book aims to help researchers, teacher educators, and classroom teachers make clear connectionsbetween practice and theory in second language learning. All the studies in this edited book are conductedin the PreK-16 classroom setting. Each chapter presents rigorous research analysis within the frameworkof sociocultural theory and provides rich descriptions of teachers' roles.The book is intended to be used in teacher education courses. The primary audience of the book is in-serviceteachers who work with second language learners (SLLs) in their classrooms including ESL/Bilingualclassrooms or regular classrooms. Since many SLLs receive instructions both in the ESL/Bilingual classroomsand in the regular classrooms, it is important to discuss teachers' roles in both settings. The secondaryaudience of the book is teacher educators and researchers who work with pre-service and in-service teachers in teacher education. This book willbe an excellent resource for book study groups and practitioners working with professional learning communities.