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.