Theoretically motivated, empirical research into task-based language learning has been prompted by proposals for task-based language teaching. These proposals aim to design and deliver task-based units of instruction that optimize the time learners spend in instructional programs, and so speed their exit from them. This volume contains papers addressing issues in task-based research into second language learning which are essential to informed pedagogic decision-making about how best to achieve this aim. These issues include research into the design characteristics of pedagogic tasks that promote the accuracy, fluency and complexity of learner language, the role of individual differences in the motivational and other cognitive variables that demands made by pedagogic tasks draw on, the extent to which tasks, and teacher interventions during task performance, promote the quantity and quality of interaction that facilitate L2 learning, and the generalizability of task-based research in laboratory contexts to classroom settings.