5. East's aim and primary concern in his book Foundational principles of task-based language teaching (2021)

Fundamentally, East’s aim is to lay a foundation, indeed several foundations, as springboards from which readers can launch themselves, should they wish to go deeper in their exploration of any aspect of TBLT.

East’s principal concern in this book is the instructed context (i.e., what goes on inside a language classroom in contrast to more naturalistic environments for L2 learning). In this opening chapter, East goes back to some very fundamental principles that have informed various approaches to classroom-based L2 teaching and learning. Some of the concepts he presents may be well known to many readers. Others may be less familiar. However, presenting these fundamental principles will help to lay an important initial foundation for subsequent chapters where he will explore TBLT, and how TBLT has developed over the last 40 years.

Reference: 

East, M. (2021). Foundational principles of task-based language teaching (p. 214). Taylor & Francis.