The last three decades have witnessed a growth of interest in research on tasks from various perspectives and numerous books and collections of articles have been published focusing on the notion of task and its utility in different contexts. Nevertheless, what is lacking is a multi-faceted examination of tasks from different important perspectives. This edited volume, with four sections of three chapters each, views tasks and Task-based Language Teaching (TBLT) from four distinct (but complementary) vantage points. In the first section, all chapters view tasks from a cognitive-interactionist angle with each addressing one key facet of either cognition or interaction (or both) in different contexts (CALL and EFL/ESL). Section two hinges on the idea that language teaching and learning is perhaps best conceptualized, understood, and investigated within a complexity theory framework which accounts for the dynamicity and interrelatedness of the variables involved. Viewing TBLT from a sociocultural lens is what connects the chapters included in the third section. Finally, the fourth section views TBLT from pedagogical and curricular vantage points.