"With the onset of the aging demographic revolution, it is essential that the general public begin planning for their future care requirements, " said Bill Novelli, chief executive officer of AARP, an advocacy group for older Americans.

CNN: Study: Americans nearing retirement ignorant about cost of care

Demographic causes and consequences of the industrial revolution, by Julian L. Simon, in The Journal of European Economic History, spring 1994.

ECONOMIST: Millennium issue

Until recently, most archeologists continued to ascribe the Neolithic revolution to a combination of climatic and demographic factors.

NEWYORKER: The Sanctuary