This book is a guide for teachers of a second language (L2), particularly English, whose aim is to develop their career in Spanish formal secondary education. It is a practical approach to the state of the art in L2 teaching and learning nowadays, meant to provide the reader with sound teaching principles and examples of good practices, based on our own experience as L2 teachers and teacher trainers. Its main audience is teachers in preparation and novice teachers just beginning in the profession, who can read this on their own or in the context of a pre-service training course. It may also be of use for practising teachers who want a hands-on introduction to the current state of L2 teaching and learning, because it is grounded on a solid empirical and theoretical background. We hope that by reading this book, teachers will be equipped with the rudiments of the profession so that they can adapt these principles and examples to the individual needs of their students and become successful mediators between materials, syllabi and the students themselves. María Fernández Aguゎro (coord.) is an associate professor at the Department of Languages and Language Teaching of Autónoma University of Madrid. She coordinates the English major of UAM’s Master’s Degree in Secondary Education. Diana Cembreros is the director of the Master’s Degree in Secondary Education at Camilo José Cela University in Madrid. She is an university professor with more than fifteen years of experience teaching at secondary and university education. Isabel Fernández Aguゎro is a secondary English teacher at IES Miguel Delibes, a state school of secondary education in Torrejón de la Calzada (Madrid). She has also been training future EFL teachers for over ten years at university level. Lourdes Pomposo Yanes is an assistant professor at the Department of Applied Linguistics of Politécnica University of Madrid.