This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book provides a comprehensive overview of English Language Teacher Education (ELTE), drawing on perspectives from the related fields of Applied Linguistics, Education and teaching English to speakers of other languages. It offers a resource for teacher educators and researchers interested in the design, implementation and support of teacher-learners in teacher education provision. The book outlines how educators can make use of technology, critical friendships, team-teaching, peer coaching, dialoguing, service learning, writing, action research and analysis of critical incidents to encourage learner teachers to engage in reflective practice. It focuses on context, considered as fundamental to the development of successful and appropriate training, education and development. The book also focuses on the linguistic knowledge of ELTE, which look at discourse, classroom discourse, world Englishes, second language acquisition, and the use of corpora.