The aim of this book is to offer theoretical and empirical contributions to metacognition in language learning and teaching from a variety of perspectives. The contributors, representing a number of different countries, continents and languages, discuss a broad range of topics concerned with metacognition in language learning and teaching in school and at the university level. Furthermore, the empirical chapters of the book employ a wide variety of established as well as innovative methodological approaches to tap into learners' and teachers' metacognition. The main audiences for this book are researchers in the field of applied linguistics, language teacher educators, teacher trainees and practising language teachers. This introduction describes how the chapters in the book relate to one another.