Descripción o resumen: The term CLIL emerged more than 20 years ago as a methodological trend in the field of bilingual education. Today, it is still an approach that brings great benefits to the learning of curricular contents through and additional language different from a student's mother tongue. The complexity of this approach, under which many different methodologies converge, makes it an instrument of multiple developments and applications, allowing each teacher to become an architect who can shape and tailor the knowledge to be imparted. In this manual, Dr. Virginia Vinuesa discusses the origin of the term CLIL, its evolution, the different methodological approaches it covers, the underlying theories and the basic principles. The aim is to demonstrate how to apply the principles of this approach in the classroom, by combining theoretical and practical aspects, and the manner, in which these same principles can be used to teach English as a foreign language. Accordingly, the manual provides a CLIL didactic unit based on a literary genre with - practical step-by-step activities on how to apply each of the 4C's, - different types of assessment: self, peer and teacher formative assessment (rubrics, games, questionnaires), - strategies to scaffold content and language, - guiding questions for the teacher to develop both lower and higher order thinking skills, - authentic language and authentic communicative situations. CLIL embodies a valuable paradigm of teaching and learning and has proven to be effective. If teachers can provide students with meaningful, challenging and authentic input, and if teachers are also ready to put this approach into practice in English lessons, a significant contribution might be made to raising the standards of foreign language proficiency.