This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book describes and problematises how World Englishes (WE) research has been and ought to be conducted. It introduces the background and methodological principles that define the methodology, identifies the strengths and weaknesses of the given methodology, and provides pointers for practical application. The book also provides an overview of three key paradigms of WE research: world Englishes, English as a lingua franca, and English as an international language. It illustrates how corpus-based approaches have become a subfield within WE research. The book discusses how WE research can be informed by ethnography and ethnographic methods as researchers examine the local experiences of individuals who speak different varieties of English. It also illustrates how corpus methods have evolved from more traditional frequency-based studies to encompass sophisticated statistical tools such as regression and classification to better understand the linguistic structure of WE.