The study reported in this book adopted a case study methodology. The case study approach is more about a unit of analysis than about data collection strategy. This study took as a unit of analysis what Lave (1988) refers to as the “whole person in action, acting with the settings of that action” (p. 17). It focuses on the ways in which the teacher, as “teacheracting,” following Lave's “person-acting” (ibid., p. 180), relate to their specific contexts of work, how they make sense of their work as a teacher, and how their knowledge, perceptions, and understanding of their work develop over time. It sees a dialectical relationship between teachers' contexts of work and the way teachers respond to them, which entails that the knowledge so constituted would be different. In order to make a rich and thick description of this situated knowledge, multiple case studies were used. Four ESL teachers teaching in the same school were selected for the study in order to highlight how teachers relate differently to what would be considered very similar contexts and how the knowledge can be constituted differently.

Yin (1994) points out that case studies do not aim at making generalizations about populations or universes, but rather at expanding or generalizing theoretical propositions. The study reported in this book does not aim to generalize how ESL teachers, as a population, develop expertise in teaching or how ESL teachers at different levels of expertise differ from one another.