The societies of central interest in this volume are characterized by recent histories of declining family size and improvements in the overall well-being of members of their populations. In every country, life expectancies are longer, earnings are higher, educational attainment has increased--by virtually any measure of human welfare, the average member of these societies is significantly better off than his or her parents. Certainly, over time, health and educational infrastructures have expanded dramatically. This makes it easier for parents to provide education and health care to their children, all else constant. Nonetheless, the rapid increase in human capital observed in the “Asian miracle” economies has in part come about because, through some combination of willingness and ability to do so, parents are committing significantly more resources to each of their children. Over time, the patterns of fertility decline and enhanced quality of life are clear. Far from clear is whether these trends represent contemporaneous responses to common underlying change, or a causal relationship of some sort. The causality question is of great interest in a study of these societies, as the quality of their labor forces is often put forth as one explanation of why the Asian miracle economies have done so well economically. Do the declines in fertility that have occurred in these societies merely reflect concurrent choices made by individuals in a changing society, or were the changes themselves enabled or facilitated by underlying demographic change? It is naive to expect that either competing explanation stands alone. Fertility decline made investments in human resources more affordable. An underlying process of “modernization” brought with it preferences for both smaller family sizes and children of higher quality. For countries less far along the path taken by the Asian miracle economies, the key question is how best to facilitate the process of change, and in this context, an important question is the role played by fertility decline. If fertility declines help to initiate economic development, encouraging such declines becomes an important development policy lever. A significant operational problem arises in attempting to separate initiating declines in fertility from fertility declines which merely accompany the broader processes of change.