Kazimierz Ajudkiewicz (1890–1963) is rightly regarded as one of the most distinguished Polish philosophers. He was a member of the Lvov-Warsaw School and a close collaborator of Kazimierz Twardowski, the founder and main organizer of the School. Like Twardowski, Ajdukiewicz was a great pedagogue and devoted much of his time and effort to organizing philosophical and scientific life; in 1953 he founded one of the most prestigious, and still extant, Polish logical journals, Studia Logica. In addition, he contributed regularly to another famous journal, Erkenntnis. Before the World War II, he was professor at the Jan Kazimierz University in Lvov. After the war, Ajdukiewicz moved to Poznań, where he was professor at the Adam Mickiewicz University as well as the President of the university for a term. Later he was nominated professor at Warsaw University, where he remained until he retired in 1961. Regarding his private life and connections with Twardowski, it is worth mentioning that Ajdukiewicz married one of Twardowski’s daughters. During the Soviet invasion of Poland in 1920, he fought as a soldier under Józef Piłsudski’s command.