This is an open access title available under the terms of a CC BY-NC-ND 4.0 International licence. It is free to read on the Oxford Academic platform and offered as a free PDF download from OUP and selected open access locations.This book provides a historiographic study of the distinction between language and dialect, a puzzle which has long fascinated linguists and laypeople alike. It offers a comprehensive account of the intriguing and complex history of the language-dialect pair, and shows that its real origins can be found in sixteenth-century humanist scholarship. The book begins with a survey of the prehistory of the language/dialect distinction in antiquity and the Middle Ages. Raf Van Rooy then provides a detailed investigation of the emergence, establishment, and development of the conceptual pair during the early modern period, from the Renaissance to the Enlightenment, when linguistic diversity was first studied in depth. Finally, the much-debated and ambiguous fate of the language/dialect opposition in modern linguistics is explored: although a number of earlier ideas were adopted by later scholars, many linguists today question the notion of a seemingly arbitrary and subjective distinction between language and dialect.