The article attempts to follow up the fate of the concept Maurice Duverger created to explain the regime of the French Fifth Republic: semi-presidential government. Duverger expounded the concept in his fundamental book Échec au roi in 1978, trying to illustrate the fact that regimes of this type worked quite differently in the seven Western and Northern European countries that institutionalized it. ‘Semi-presidentialism’ is now widely, but very often controversially, used. The recent appearance of such regimes in newly democratizing states points to the fact that this form of government is often the preferred solution in times of transition. A critical review of Duverger's concept seems expedient as the diversification of these regimes raises new and perhaps intriguing questions. Due to the rejection of Duverger's concept or its ignorance in parts of the European scientific community, it is necessary to defend it as an important tool for political analysis. Moreover, it opens the opportunity for the examination of fundamental problems in political science.