In the past 15 years, English as a lingua franca (ELF) has evolved from a 'niche topic' of a relatively small group of specialists to a highly productive research area that now has a firm place on the map of linguistics. Looking back (as well as forward), this edited volume addresses perspectives and prospects of ELF in connection with other areas of linguistics. It is the first volume that brings together ELF scholars with experts from a wide range of areas in linguistics (such as corpus linguistics, sociolinguistics, historical linguistics, language pedagogy, language policy, intercultural communication). Adopting an inter-/transdisciplinary approach, the book traces the impact that discussions about ELF have had - or may have - beyond the study of ELF as such: for the conceptualization, description, methodology, pedagogy and politics of 'English'. As the book combines external perspectives on ELF, provided by well-known scholars in diverse fields, with a smaller number of internal perspectives provided by prominent ELF scholars, it will be of interest not only to students and researchers interested in ELF, but also to students and scholars in Applied Linguistics, Sociolinguistics and Intercultural Communication.