Dr. N.K. Das had the privilege of conducting systematic social anthrpological research in Nagaland and other regions of North-eAst during 1976-88. Based on the material thus collected, Dr. Das has critically examined the ethno-historical and socio-political processes and factors causing ethnic conflict in sensitive North-East India. Using anthropological insight and historical anlaysis of pre-state segmentary social system among the Zounuo-Keyhonuo Naga, and examines the processes of state formation among the Ahom, Kachari, Meitei, Jaintia, Koch, Karbi and Khasi tribes in time and space dimensions. Other crucial subject matters discussed in this pioneering work are 'concept of tribe' fallacy of unilineal descent theory', 'matriliny to patriliny', 'peasantization','Inequality', `slavery', `social-stratification',`sanskritzation', `Christinaity', `Naga', `Mizo', `(Udayachal) Assam', `GNLF', `TNV', `Karbi',`Bodo' movements, and cultural revivalism.