２１世紀の社会言語学の風景の中で英語教育を捉え直すために「国際語としての英語教育」（TEIL）分野の新たな全体像を理論、主要な枠組み、教授・評価の方法、革新的アプローチ、環境的差異、教師教育の視座から示す。Reframing English language, language teaching, and teacher education to match the new sociolinguistic landscape of the 21st century, this handbook analyzes Teaching English as an International Language (TEIL) in seven key areas: Theoretical considerations; Major frameworks and proposals; Principles and practices of teaching and assessing English; Innovative approaches, varied contexts, and transformative practices; Diverse teaching settings and populations; Teacher education and professional development; Research developments and future directions.