The history of Southeast Asia has been greatly influenced by its wide topographical diversity. Maritime Southeast Asia is apart from exceptions like Borneo and Sumatra a patchwork of recurring land-sea patterns on widely dispersed islands and archipelagos. A discontinuity, that admitted moderately sized thalassocratic states indifferent to territorial ambitions where growth and prosperity was associated with sea trade. Mainland Southeast Asia with a continuous, but rugged and difficult terrain provided the basis for the early Khmer and Mon civilisations. However, an extensive coastline and the south—and south-eastbound major river systems of the Irrawaddy, Salween, Chao Phraya, Mekong, and Red River always have directed focus, local trade, socio-cultural and economic activities towards the Indian Ocean and the South China Sea.

Rajesh Chandra has worked as a Professor of Medieval Indian History and Dean of Social Sciences in Prestigious University. He is also serving as the Secretary General of the many organisations. His works have been published in many books and journals.