The general aim of this volume, as its title indicates, is to present and discuss current empirical, pedagogical and technological approaches to the acquisition and teaching of non-native (second -L2, third - L3) languages in the context of the multicultural society in which we are immersed. Learners are the protagonists of the volume in that the various chapters focus on the non-native language learning and non-native language teaching principles, mechanisms and processes that lead them to acquire and use a language other than their native language or L1. A clearly innovative aspect of the volume is the fact that it deals with learners that come from all walks of life, as there are foreign and second language learners, third language learners, simultaneous and sequential bilinguals, immigrant speakers, heritage speakers and speakers of minority languages. The volume offers a multicultural perspective in that the learning and/or teaching accounted for by the various chapters takes place in different geographical areas, in different communities and in either natural or institutional settings. The linguistic dimension of that multicultural perspective is the many languages that are described, analysed and compared, be it as target (L2 or L3) or as source (L1) languages. This linguistic dimension is further enriched by the fact that there are chapters dedicated to the various areas of language, which implies that in some cases we gain an understanding of how syntax is acquired and taught while in other cases the object of inquiry is the sound system or the morphological and discourse patterns of the target and the source languages. One more appealing aspect of the volume pertains to the variety and topicality of the methodological approaches used by the various researchers, as they go from the use of surveys or the analyses of corpus data and offline experimental tasks to the employment of eye-tracking experimental tasks or the description of electrophysiological techniques (i.e., event-related brain potentials).] Esta obra completa el catálogo de Thomson-Reuters Aranzadi.