 He earned a Ph.D. in 1928 under Wacław Sierpiński and habilitated at the University of Warsaw in 1934.He published works on mathematical logic, set theory, cardinal and ordinal arithmetic, the axiom of choice, the continuum hypothesis, theory of functions, measure theory, point-set topology, geometry and real analysis.He served as an assistant professor at the University of Warsaw from 1935 until the outbreak of war in September 1939.