Human life expectancy, in the space of a mere century or so, has become much longer than ever before. This primarily reflects the improved social and physical conditions of living, along with the strengthening of civil institutions; circumstances which, in particular, have greatly diminished childhood deaths from infection and malnutrition. We have thus partially reined in two of the four biblical Horsemen of the Apocalypse: Famine and Pestilence on their black and pale horses, respectively. Meanwhile, the other two Horsemen, War and Conquest, still roam menacingly on their red and white steeds.

Warfare continues. The recent conflicts in Kosovo, Chechnya and Sierra Leone testify to the destructiveness of modern firepower and the attendant toll in civilian casualties. Conquest persists, albeit mostly in modern commercial guise, reflecting aspects of economic globalisation and deregulated trade. The ascendancy of free markets, while conferring some health gains via material improvements and the restoration of dietary diversity, adversely affects the health of many vulnerable populations. Our modern economic system has widened the rich–poor gap and, in many settings, has weakened social institutions, eroded environmental conditions, fostered exploitative labour practices and displaced peasant farmers onto more marginal land. Meanwhile, in the world's expanding cities, commercial pressures promote cigarette smoking, automobile dependency and the consumption of energy-dense processed foods.

The profile of human health remains mixed. The health of the wealthy and fortunate continues to exceed that of the poor and disadvantaged, both between and within countries.