Why is it rational to be irrational? The book reveals the strategic role of emotions in human behavior. The author attempts to explain how emotions motivate people to act contrary to their apparent material interests and why such behavior can be beneficial. The main hypothesis of the work is formulated in terms of economic theory; real ethical dilemmas - the willingness to rush to the aid of a stranger, love collisions, the thirst for revenge, etc. - are considered in relation to speculative versions of the prisoner's dilemma and the "free rider" problem. Frank relies on empirical materials from psychology, evolutionary biology, and culture to show how noble human impulses were not only able to withstand the harsh pressure of the material world, but were, in fact, generated by it. This result is explained paradoxically: just as it is impossible to be intentionally spontaneous, in many situations the conscious pursuit of selfish interest is simply incompatible with its achievement. The book will be useful to representatives of social sciences, as well as to anyone interested in the motivation of human social behavior.