The purpose of this research is to understand the development of social complexity and the origins of the early state in the Upper Mun River Valley (UMRV), Northeast Thailand during prehistory. By using the human skeletal remains from the excavation at Ban Non Wat archaeological site, Phon Songkhram Sub-district, Non Sung District, Nakhon Ratchasima Province between 2002 and 2007. The cultural chronology can divide into four phases from the Neolithic continuity to the Early Historic, approximately 1,500 – 3,700 BP.

The methodology used in this thesis consisted of the stable strontium, carbon, and oxygen isotope analysis of human tooth enamel. Combined with the study on non-metric dental variation and the geometric morphometric analysis of the cranial shape. To investigate the question about the population affinities, migration, kinship system, diet and subsistence pattern, social organization, including the climate and environmental change that shaped the development of social complexity. The result – four articles have been published in the academic journals, there are:

1) Social organization in the Prehistoric Mun River Valley: The story from the isotopes at Ban Non Wat.

2) Mixed economies after the agriculture revolution in Southeast Asia?

3) Moving peoples, changing diets: Isotopic differences highlight migration and subsistence changes in the Upper Mun River Valley, Thailand.

4) Isotopes and osteology: Using the multi-disciplinary approach to establish population affinity at Ban Non Wat, Thailand.

In brief, there were probable some migrants arrived at Ban Non Wat in the Neolithic phases. The cranial morphology of the individuals who buried in the flexed burial was slightly difference when comparing with the supine individuals, and no clearly evidence of any kinship system. Climate change had increased temperature in the transition from the Bronze to the Iron Age would had affected and correlated to the diet and subsistence change in this population. And lastly, the social organization of Ban Non Wat was likely the idea of a heterarchical more than a flexible hierarchical society.