For the one billion people living in the world's poorest countries, where the burden of disease is highest, those who are born or who die are still not counted. The health profile of these populations is akin to an iceberg: the bulk of reliable data remains hidden. This great information void is a major, long-standing constraint to the articulation of effective policies and programs aimed at improving the health of the world's poor. As such, it perpetuates profound health inequities in the developing nations of the South. The INDEPTH Network is working to fill this information void. It links research sites that are currently able to effectively monitor the health and demographic status of their local populations. By connecting these sites, the network enhances their research capacity and abilities to set priorities, allocate resources, make decisions, and define relevant research and development agenda. This book presents new and critical data recorded at the INDEPTH research sites. The impact of the HIV/AIDS pandemic in sub-Saharan Africa is leading to demographic changes in mortality patterns hitherto unseen and undocumented. This publication addresses this fundamental gap and, in doing so, describes patterns of mortality that current models are unable to provide. Starting with a description of the basic methods used, this volume summarizes mortality data, compares mortality patterns at INDEPTH sites, and reports on mortality patterns for Africa. Each INDEPTH site has contributed a chapter in which it describes itself and the data it is contributing.