This essay tackles a bimillenary problem in psychology, ethics, economics, and political philosophy: that of the relations between wealth and well-being. What are they, and should we live for pleasure, or rather seek to live a full and useful life? This is the ancient dilemma between hedonism, the cult of pleasure, and eudemonism, the search for a good life. Economists, almost without exception, have opted for hedonism, but they have not found out what percentage of the goods that ordinary people want are not merchandises. This gap is currently being filled by psychologists, sociologists, socioeconomists, and other workers in the new "science of happiness". Their main finding, that happiness is not for sale, might surprise the orthodox economists. On the social level, the former problem, concerning individuals, gets translated into the question of national development: what kind of development should we seek, and for whom? In particular, should economic growth be prioritized, or should we promote the simultaneous development of all sectors of society, including the political and cultural? In either case, should development benefit the chosen few or everybody? And should it enhance the well-being of the individual and make that of her offspring possible? This problem, of course, lies at the intersection of three sciences--psychology, economics, and political science--and two chapters of philosophy--ethics and political philosophy. Consequently, anyone daring to propose original solutions to the problem in question will risk being criticized by experts distributed among these five fields, who are not used to talking to one another.