This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book presents the Teaching English-language development (ELD) is often considered challenging work, but for the right kind of teacher, it is the only work imaginable. Those who teach ELD are fortunate because the authors find learning about language and languages compelling. ELD holds an obvious attraction for those of us who are compelled to learn more about language and languages, not only those who want to learn different languages, such as French or Finnish. Recent immigration patterns in Europe also underscore the intersection of geopolitics and ELD teaching. The sociologist Louis Wirth once said that the proper definition of culture is "everything that take for granted". One of the more recent challenges in the study of culture in schools and one that appears to be long lasting is the relationship between the culture of the teacher and the culture of the students.