Against a backdrop of theory, policy documents, and examples of practice, this book weaves together research in both secondary and tertiary education, with a particular focus on the key stakeholders involved in EMI: the teachers and the students. Whilst acknowledging that the momentum of EMI is unlikely to be diminished, and identifying its potential benefits, the author raises questions about the ways it has been introduced and developed and explores how we can arrive at a true cost-benefit analysis of its future impact.