This chapter introduces the book that explores the critical role of professional development in English Medium Instruction (EMI) across global higher education contexts. As universities increasingly embrace EMI to enhance their international profiles and educational quality, the need for comprehensive professional development programs has become paramount. The book presents diverse international perspectives on EMI professional development by examining challenges faced by educators and existing training approaches across different regions, e.g. North Africa, Turkey, Italy, Brazil, and South Korea. Through ten chapters in the rest of the book, contributors analyze various aspects of EMI professional development, from language proficiency and pedagogical skills to cultural competency and assessment literacy. The volume emphasizes that effective EMI implementation requires more than just language training, which underscores the importance of context-specific, comprehensive approaches that address both linguistic and pedagogical challenges. By sharing experiences and best practices from various contexts, this book provides valuable insights for educators, administrators, and policymakers involved in EMI implementation.