This book provides a clear and accessible introduction to the main methods of analysing samples of learner language. It examines the theoretical and research bases for the different methods, and thereby serves as an introduction to the field of second language acquisition research. The book is intended for students on postgraduate courses in TESOL or Applied Linguistics, or for teachers wishing to do action research to find out more about how learners learn language. Who is it for Graduate students, teachers, researchers in Applied Linguistics