This book on regional historical demography is the first major study analysing the factor responsible for the growth and variations in the population of Assam during 1881-1931. The book fills up, for the first time, the gaps in the population statistics of Assam, particularly in the field of fertility, mortality and migration rates. The internal migration factor has been decomposed into main historical streams and then studied and analysed in depth. The work is methodologically oriented and offers estimates of the population parameters with the aid of appropriate growth curves and other statistical tools and techniques. The links of population events with the socio-cultural milieu of Assam in a historical perspective have been adequately probed by the author. Besides being a useful reference work for the postgraduate students majoring on population and demography, the book would provide much new information makers and economic historians who are interested in pursuing a scientific study of the behavioural dynamics of population in the Brahmaputra Valley, also called the Assam Valley. The variations in population have been studied and analysed componentwise. While it does not purport to be a comprehensive text on the economics of population, important questions of demography are discussed in the context of the books main aims. The book should also be useful as prolegomena for a scientific and dispassionate understanding of the current movement for the deportation of the illegal infiltrators coming into the north eastern region from neighbouring countries.