This paper considers Richard Thaler’s contribution into the exploration of economic behavior and its deviations from the predictions of the classical economic theory. The paper summarized the 2017 Nobel laureate in economics contribution in several areas: the study of mental accounting system, social preferences, endowment effect and the self-control problem. It also describes the effect that Thaler’s research had on the introduction of a new type of economic policy – the libertarian paternalism.