What is more conducive to economic development of a nation-specialisation or diversification? Are regions within a developing economy experiencing divergence or convergence as they embark on high growth path? The learnings from the India story has valuable lessons on such aspects for other developing countries and so this book is a deep dive into the regional economy of India. A region's ability to experience growth is to a large extent determined by its ability to attract either industry or people. This phenomenon is known as agglomeration and affects concentration of firms, development of industrial hubs, policies towards special economic zones, flows of labour and capital, formation and growth of cities. Given the size and diversity within each state in India there is an urgent case for going one step below to identify homogeneous units at a sub state level, viz., NSS regions, something which this book seeks to address.