Human population growth is a serious biospheric problem yet is largely overlooked. Because of the neglect of demography, environmental policies--while well-intentioned--are unlikely to succeed. This book gives a concise review of world fertility rates and population growth, and offers a valuable summary of studies of the impact of overpopulation on the biosphere. In addition, the book explains key demographic variables to consider when formulating law and government policy relevant to childbearing, and it summarizes findings of social science research--findings that contradict popular assumptions about the impact of government interventions addressing the frequency of childbearing and immigration.