This book contributes to the growth of interest in Content and Language Integrated Learning (CLIL), an approach to second/foreign language learning that requires the use of the target language to learn content. Within the framework of European strategies to promote multilingualism, CLIL has begun to be used extensively in a variety of language learning contexts, and at different educational systems and language programmes. This book brings together critical analyses on theoretical and implementation issues of Content and Language Integrated Learning, and empirical studies on the effectiveness of this type of instruction on learners' language competence. The basic theoretical assumption behind this book is that through successful use of the language to learn content, learners will develop their language proficiency more effectively while they learn the academic content specified in the curricula.