This book examines the nature of language teacher development and what teachers need to know in order to be able to teach effectively. It explores different approaches to teacher training, and offers many practical suggestions for the kinds of activities that can be used in teacher training programs. It also surveys theory and research on second language teacher development. The text seeks to articulate a theoretical framework for the field of second language teacher education, as well as clarify some of the issues involved in designing and implementing pre-service and in-service teacher education programs. It is a book that can be read by teachers in MA or postgraduate courses, as well as teacher trainers in language schools and universities.