In this chapter, the reader will be introduced to the rationale of the volume, becoming familiar with the turns currently characterising Applied Language Studies. Special attention will be given to the multilingual turn, to the visual turn and to the way subjectivity becomes a necessary approach in the study of multilingualism as lived and as experienced by individuals. The reader will then be acquainted with the tripartite structure of the volume (The Multilingual Self, The Multilingual Learner and Multilingual Teacher Education) and with a detailed description of each chapter.