The document discusses patterns in world population growth, comparing trends in more economically developed world (MEDW) and less economically developed world (LEDW) populations. MEDW populations are growing more slowly with fertility rates below replacement level, while LEDW continue to grow at 1.8% annually, though rates are declining as countries develop. The concepts of overpopulation, underpopulation, and optimum population are introduced based on relationships between population size, resources, technology, and living standards.