Professor Zdzislaw Chlewinski was the creator and head of the Department of Experimental Psychology at the Catholic University of Lublin. His main interests were focused on decision-making and risk-taking, and in general – on human cognition, including errors in thinking. As a scholar, researcher and educator, he was concerned with methodological precision and the use of computational methods in psychological research. As a man of science and a Catholic priest, he was distinguished by his open-mindedness, cognitive curiosity, tolerance and social commitment. The article presents the Professor's scientific profile and research, publication and organizational achievements.