This paper begins with a consideration of the historical roots of task-based teaching, especially as they relate to communicative language teaching. It notes significant common elements between the notion of 'communicative activity' and that of 'task'. But differences are also noted, to do with the concepts of 'message focus' and 'form defocus'. A view of the role of tasks is put forward based on information-processing requirements and the need gradually to permit learners to be able to handle different levels of real operating conditions. Finally, a proposal is put forward for task-based teaching to run alongside more conventional language teaching, with the two components (task-based and 'conventional') deliberately not being linked in terms of language content.