The book is comprised of three components. The first component analyses the creative contribution to the theory of imperatives and norms provided by 20th-century Polish researchers. The second component summarizes their reflections and considerations. The third component is an anthology of the classic writings of Polish authors of the time; it constitutes an illustration of the first part and indicates that their research covered practically the whole scope of this theory. Jacek Jadacki (born 1946) is professor at Warsaw University. His scholarly production includes approximately hundred works spanning almost every domain in philosophy: from logic, through ontology, epistemology, aesthetics and ethics, to the history of these disciplines. Among his more than twenty books are Possible Ontologies (with Zdzisław Augustynek; 1993), From the Viewpoint of the Lvov-Warsaw School (2003), and Polish Analytical Philosophy (2009). His pupils include such well-known figures of modern Polish thought as Anna Brożek, Mariusz Grygianiec, Joanna Odrowąż-Sypniewska, and Mieszko Tałasiewicz.