An alarmingly well-documented look at the need to reassess retirement policies in the US. Owing to falling birth rates and longer life expectancies, the authors aver, ""Social Security institutions and their corresponding retirement-age policies appear to be out of joint with socio-economic realities."" In other words, "". . .the more we retire people with better and better retirement incomes, the sooner we will come to a point beyond which we cannot continue such a policy."" Projecting current demographic and early-retirement trends, Sheppard and Rix estimate that by 2020 every 100 workers will be surpporting 45 pensioners, against just 30 in 1975; further advances in gerontology could increase this proportion. Eventually, they maintain, the expense may become prohibitively burdensome for society. In addition, the declining availability and rising cost of energy and natural resources could lead to a situation where the country will need all able-bodied adults ""to staff a more labor-intensive economy."" As an alternative to the problems that will develop if the public and private sectors take no action to reduce the census of non-working oldsters, the authors recommend deliberate shrinkage of the retiree population (by more flexible retirement rules) to a level where those in it can maintain an ""acceptable"" standard of living. While Sheppard and Rix do not discuss any of the new difficulties that might result from retirement-policy changes, they have defined and spotlighted an important issue overdue for debate.