In this state-of-the-art paper, we will review the literature on Content and Language Integrated Learning (CLIL) through an analytical lens. It is essential to understand how CLIL has evolved and integrated into the educational literature as a dual-focused educational approach with multiple dimensions and uses. CLIL has been the topic of countless debates since its inception. What is CLIL? Who should teach it? Is CLIL the same as immersion or content-based instruction (CBI)? What are CLIL’s theoretical underpinnings? We consider that an accurate description of the CLIL approach would not be possible without understanding its historicity, political and social context, reasons behind its inauguration, and the theoretical underpinnings that distinguish CLIL from other similar approaches. Relevant literature illustrates that the North American immersion education, which is often a source of confusion and debate among CLIL circles, was used as a point of departure in the inception of CLIL and inspiration during its infancy. However, CLIL has evolved significantly since its inauguration in the 1990s and now it represents an approach that integrates both language and content teaching both in foreign language and bilingual education contexts. EMILE was not created from scratch. Its inception was influenced by a multitude of factors such as (a) historical, political, ideological and societal factors of the 1980s, (b) bilingual language teaching approaches that use second/foreign languages as medium during content teaching, (c) research outcomes on bilingual education, (d) current foreign language approaches and practices, and (e) the alternative theories of learning that drew on the postmodernist philosophies that emerged in the 1980s.