Over the past two decades, task-based language teaching (TBLT) has gained considerable momentum in the field of language education. This volume presents a collection of 20 reprinted articles and chapters representative of work that appeared during that period. It introduces readers to foundational ideas and themes that have marked the emergence of TBLT. The editors provide a first chapter that locates TBLT within broader discourses of educational practice and research on language learning and teaching. The book then features four sections consisting of important, often difficult to find, writings on major themes: fundamental ideas, approaches, and definitions in TBLT; curriculum, syllabus, and task design; variables affecting task-based language learning and performance; and task-based assessment. In a concluding chapter, the editors challenge simplistic notions of TBLT by reflecting on how this body of work has initiated the possibility of a truly researched language pedagogy, and they highlight critical directions in TBLT research and practice for the future.