Understanding how second language task-based performance can be raised is vital for progress with task-based approaches to instruction. The chapters in this volume all attempt to advance this understanding, and do so within a viewpoint which assumes limited attentional capacities and accounts for second language speaking based on Levelt's model of first language speaking. Six empirical chapters present original studies. They explore the topics of task planning, familiarity of information in a task, task repetition, task characteristics, and the effects of using post-task transcription. The studies interweave with and build upon each other, reflecting their conjoint focus on how second language learning memory and attention limitations shape their performance in using the target language. In the concluding chapter the accumulated findings across these studies are discussed in terms of the nature of preparation for a task, the role of task structure, the respective claims of the Tradeoff and Cognition Hypotheses, the role of selective attention, and the implications of the studies for pedagogy. The book is a central reference for students in psycholinguistics, second language acquisition, and task-based language teaching.