Much ado about demographics: how the ""birth dearth"" and greater longevity is turning America into a nation of oldsters. In the wings are 76 million baby boomers; when this group starts reaching retirement age in the 21 st century's first decade, oldsters will dominate our culture and economy. But by 2020 there will be only 1.78 working Americans to support each retiree at a whopping Social Security bite of $25,000 a year. Dychtwald (who's president of Age Wave, Inc, a consulting finn; author of Wellness and Health Promotion for the Elderly, etc.) and Flower raise this specter, then skirt it. They do suggest that Social Security adjustments may ameliorate the situation, but then they swing into the opportunities the brave graying world awaiting us will present for individuals and industries. They foresee a ""cyclic lifestyle"" when life expectancy reaches 80-90 years. People will then spread out retirement by working to a later age and ""cycling in and out of several different careers. . .each interspersed with periods of rest, recreation, retraining, and personal reflection."" Industries will focus on adults of 50-plus who already account for 40% of consumer spending. Retirement housing complexes will proliferate and may be geared to interests such as horticulture, a kind of Esalen self-development, etc.; adult education will boom; medicine bottles will be easier to open; and on and on. If Dychtwald and Flower say nothing new, they say it very well--which may be why their book is a choice of several book clubs and why the first printing totals 150,000.