A Cornell economist questions today's pervasive belief that those who put their material self-interest ahead of moral or emotional considerations are more successful and rational than those who don't. Frank agrees that materialistic considerations are important, but points out that people who make self-sacrifices for others are not necessarily irrational or doomed to a penurious existence. In making short-term sacrifices, they avoid painful feelings of guilt or shame, and they may well lead more successful lives than out-and-out opportunists. This idea, he says, rests on a simple paradox, namely, that in many situations the conscious pursuit of self-interest is incompatible with its attainment. He also points out that every society requires some self-sacrifice, and wonders whether the current emphasis on the supposed benefits of self-interest is not eroding the very character traits that nourished democratic capitalism. Frank produces considerable evidence (including behavioral research tests) that indicates Americans value ethical behavior, are more honest than is generally assumed, and despise unbridled opportunists. He supplies little evidence, however, to demonstrate that moral behavior is conducive to material success - although he does mention the value of a good reputation. Solid food for thought for economists, behavioral scientists, and more general readers of a philosophical or scientific bent. (Kirkus Reviews)