Please note: This is a companion version & not the original book. Sample Book Insights: #1 The most obvious physical constraint on fertility is the length of the fertile period, which has been decreasing from about 17 years in preindustrial societies to less than 13 years in today’s Western world. #2 The shift from high to low fertility took about two centuries in Denmark and 170 years in Sweden. No country has been able to stop the fertility decline at the replacement level and achieve a stationary population. #3 The most common measure of human quality of life is the gross domestic product per capita, but this does not take into account economic inequality or the social net available to disadvantaged families. I prefer to use the Human Development Index, which combines life expectancy at birth and educational achievements with the gross national income per capita. #4 The lowest infant mortality rates are found in small, homogeneous societies with very low birth rates. It is difficult to maintain low infant mortalities in larger, heterogeneous societies with high rates of immigration from less affluent countries.