Brookings economist Aaron--recently (1977-78) Assistant Secretary for Planning and Evaluation, HEW--briefly, cogently, and warily examines the major issues surrounding Social Security, welfare reform, and national health insurance; still committed to government action, he's more than ever conscious of impediments. As regards Social Security, Aaron stresses the need for equitable treatment of the family--and, in particular, for providing benefits to women as individuals, not as dependents or adjuncts. A good, radical solution presents itself: a ""double-deck"" Social Security system which would provide (1) a flat grant for all the aged and disabled and (2) a pension strictly proportional to earnings. But to its critics, politically-potent labor unions and old-age groups, this scheme raises the specter of a means test if the universal grants were paid for by general revenues. Aaron regards the fear as exaggerated--and groundless if financing were based on a special surtax or an earmarked portion of the income tax; still, it effectively blocks the scheme. Also of immediate concern is raising or lowering the retirement age, a decision complicated by lack of information--on whether Social Security has encouraged or followed the trend toward early retirement; on whether or not retirement is actually healthful. In the area of welfare reform, Aaron is particularly illuminating on work incentives, and the discordance between popular beliefs and the results of research. He also reviews the startling findings of the Seattle-Denver Income Maintenance Experiments, which seemed to demonstrate that offering aid uniformly to one- and two-person households (as the present system does not) increased the rate of family breakup--by, perhaps, allowing unhappy partners to separate. In disputing this inference, Aaron cites statistical anomalies and, crucially, differences between such experiments and ""any real-world program."" On national health insurance, he scores by setting forth, clearly and systematically, the various areas of controversy (benefits and cost sharing, system reform, the state role, administration, reimbursement, financing) and pinpointing the effect of each decision on each entrenched interest. A tight little package of expertise, candor, and political wisdom.