An international conference organised in Madrid 1934 by l'Office international des Musees (a predecessor of ICOM) became known as the first museological event. From that time on, the concept of 'museology' became a permanent part of the vocabulary of the European humanities, and denotes a science dealing with the construction (architecture) and administration of museums. Its complete, and still topical, definition was proposed in 1981 by Georges Henri Riviere (1897-1985): Museology is an applied science about the museum. Its domain encompasses reflections on the role of the museum in society, research and conservation, manners of presentation, animation and dissemination of architecture raised for museum purposes and 'museum-like' architecture (adapted for the purpose of museums), investigations of the sites and obtained objects, selections, as well as typlogy and deontology. Museography is, according to Riviere, a set of technical and practical principles implemented in museums. Moreover, he also distinguished settings, a range of creative activity taking into consideration the formal and material outfitting of exhibitions. Riviere, and subsequently many other theoreticians-museologists, drew attention to a fundamental difference between museology conceived as a science making use of many active domains (philosophy, aesthetics, sociology, psychology, management, theories of financial law, and the historical, natural sciences and exact sciences) and the history of museums perceived as one of the specialisations of history. The term 'museum studies' has been used in Poland since the 1940s (and was applied already by Stanislaw Lorentz). In time, the range of its meaning has become very wide, and now includes all the questions associated with the functioning of museums and their history, as well as assorted philosophical and sociological reflections. The extent to which it had been adopted by the Polish language is evidenced by the fact that the title 'Muzealnictwo' has been granted to the only Polish annual about museum studies, for which this article has been written. The term in question, therefore, embraces both museology, museography and the history of museums, a fact which makes it even more difficult to formulate a more precise definition. At the beginning of the twenty first century, museology is becoming one of the most dynamically developing sciences; on the one hand, this is the outcome of the pan-museum cultural and social policy which regards the museum as one of the most relevant instruments for shaping non-formalised education. On the other hand, museology is becoming the domain of artists who apply its experiences and theories for building their own projects, frequently based on the 'religion of the object', practised in museums.