Fundamental concepts of population studies

The massive increase in population density is the major contributor to concerns about energy sources, housing shortages, hunger, environmental degradation, and the global shift of manufacturing jobs to less developed nations. In order to deal intelligently with a future that will be shared with billions more people than today, we have to understand why the populations of most countries are growing (and why some are not) and what happens to societies as their patterns of birth, death, or migration.