This book examines the intervening mechanisms that bring about transition from natural to controlled fertility at micro level, on the basis of empirical data collected through a survey specifically designed for the purpose. In this background it is clear that studies relating to demand for children, supply of children and costs of fertility regulation, which are the causes of shift from natural to controlled fertility are of particular value. The findings of such studies may have several important 'policy implications, which will be useful to the policy makers in reducing fertility.