Intuicyjny formalizm Stanisława Leśniewskiego

The paper presents two volumes of Stanisław Leśniewski's Pisma zebrane [Collected Works] edited by Jacek Jadacki and published in 2015 by Towarzystwo Naukowe Warszawskie and Wydawnictwo Naukowe Semper. The focus here is on the works published in the second period of Leśniewski's scholarly activity, when he created his system of foundations of mathematics. However, in the publications it was not presented systematically and comprehensively. The article also explains why Leśniewski's view is called "intuitive formalism".