Teacher research is recognized, in ELT and education more generally, as a powerful transformative strategy for teacher development and school improvement. This volume provides original insights into this issue by focusing on the processes involved in becoming and being a teacher researcher. Contributions highlight these processes from two particular perspectives: from that of teachers themselves as they experience what becoming and being a teacher researcher involves; and from that of those who facilitate teacher research, with a focus on the practices and principles they employ in supporting teachers.