The two major focuses of physical anthropology are human evolution and human variation. Man as he walks the earth today is the product of an evolutionary process that has been going on for several millennia. One aspect of the study of man deals with the large scale or long term evolutionary changes; the other attempts to understand the short–term evolutionary trends in man at a micro level. Dr. Das has selected the north eastern region of India for an indepth study of the micro-evolutionary trends that can be seen among the diverse ethnic groups inhabiting the area. Case studies of major ethnic groups like the Boro, Khasi and the Chutia help in establishing these processes. The author has brought to bear on the subject his deep learning and experience as well as a knowledge of the most advanced techniques employed in such studies. His bio-social analysis of the peoples of this conflict-prone and tension-ridden region should go a long way in helping to understand the transformations that have been taking place in the area. Dr. Das’s scholarly volume, the fourth in the Ranchi Anthropology Series, is an extremely valuable addition to the subject of physical anthropology which intersects allied disciplines at several points. About the Author: B.M. Das was educated at Calcutta University (M. Sc., 1953; Ph. D., 1959; D. Sc., 1973). He was an Alexander von Humboldt Fellow and did post-doctoral research in the Institute fur Anthropologies, Freke Universitat, Berlin (1968-70) and Institute fur Genetik, Medizinische Hochshule, Hannover (1975), Federal Republic of Germany. He was professor and head of the department of anthropology in the Dibrugarh University, Assam (1973-76) and currently is professor and head of the department of anthropology in the Gauhati University, Assam. He has published a large number of research papers and notes in various journals of India and abroad. Further, he has published ten popular books on anthropological topics in Assamese besides several popular scientific articles in Assamese and English. Among his published books are The Ethnic Affinities of the Rabha (1960); Kaharpara: A Report on Socio-Cultural Survey (1964); Out lines of Physical Anthropology (1961) Fifth edition (1980); Anthropometry of the Tribal Groups of Assam, India (1970); variation in Physical Characteristics in the Khasi Population of North East India (1978); Contemporary Anthropological Research in North east India (edited) 1974.