The main aim of the paper is to present the institution of 'habilitacja' (habilitation, either the status connected with the right to give lectures at a university or, currently, a post-doctoral degree) in Polish state higher education in the years 1920-1939, and the legal framework relating to it. Additionally, the aim of the paper is to show the difference between the status of 'habilitacja' in that period and in contemporary Poland (after 1989). The paper is based on the analysis of source documents and involves an analysis of legal acts from the period of inter-war Poland, which have been confronted with the statutes of selected tertiary schools of that period. The paper provides essential information concerning 'habilitacja' nowadays (according to the legal framework as in force on 1 February 2009), and presents the system of higher education in inter-war Poland, together with a classification of tertiary schools. The legal documents concerning 'habilitacja' and the position of docent are examined, with special focus on two parliamentary acts regulating higher education, of 1920 and 1933. It then proceeds to describe in detail the so-called 'right to lecture' (Lat. venia legendi), taking into account the most important issues relating to how it was implemented. The paper also discusses the very nature of 'habilitacja' and the position of docent. For clarity of presentation, the author of the paper makes occasional references to the current state of affairs in Poland. The penultimate section of the paper is devoted to the role of decision-making bodies in the academic system (such as the faculty council, or the general assembly of professors) in granting the right to lecture. The last section of the paper deals with the procedure involved in the granting of 'habilitacja', with a precise account of its particular stages. The analysis in the paper points to fundamental differences between the position of docent in a state tertiary school in inter-war Poland and the current degree of 'doktór habilitowany' (habilitated doctor) .