Description: Concomitant with the industrial revolution, the function of providing old age income shifted from families and local institutions to government social security and private pension plans. The history of this change in the U.K. and U.S. is reviewed. A simple mathematical model provides insights into the role played by three rates [the rate of increase of the working population, the time preference rate, and the rate of real wage growth] in determining optimum funding policy. From Actuarial Research Clearing House 1994, Vol. 2.