This book is about connectivity between South Asia, East and Southeast Asia, which are often thought in conventional wisdom as three separate regions. However, ancient artefacts found across the three regions show that their connection, especially the influence of Indian culture and religious practices, run deep. The modern world has witnessed the rise of India (the largest country in South Asia), China, South Korea and Japan (in East Asia), and the Association of Southeast Asian Nations (in Southeast Asia). Therefore, connecting the three regions has been part of political thinking of regional leaders in the so-called “Century of Asia”. The discussion and analysis in each chapter of the book through the lens of history, culture, religion, security, political and economic cooperation from the ancient to modern time offer a primilary answer to the question of why connectivity and links between the three regions are now more important than ever and need to be strengthened.