Throughout most of the nineteenth century, economic growth had, at best, a minimal impact on life expectancy. The critical causes of the modern rise in life expectancy are the emergence of new knowledge of disease and new technologies of disease control. But were these developments in the control of contagious disease the product of the institutions that are said to be responsible for economic growth, namely, free markets, private property, and freedom of contract? This question was touched on in the previous chapter, but it is considered more fully here. As a basis for forming an answer, I examine in some detail the historical experience of mortality in developed countries (DCs) and developing countries (LDCs) over the past two centuries. Although the experiences of the two sets of countries are almost always treated separately, I see them as a continuum because, in both, all or most of the improvement of life expectancy is due to the great reduction of major infectious diseases. The experience since the 1950s of today's developed countries is not included because of the shift in their disease environment primarily to diseases of older age.

The first section focuses on the particular techniques by which infectious disease has been brought under control and life expectancy has been increased so dramatically.