Hugo Steinhaus was a Polish mathematician who was an influential member of the so-called Lvov School, based at the Jan Kazimierz University in Lvov, which also included Stefan Banach and which focused on problems in functional analysis, real functions, and probability in the 1920s and '30s. Early on, Steinhaus's work revolved around applications of the Lebesgue measure and integral. In 1923 he published the first rigorous account of the theory of tossing coins based on measure theory, and in 1925 was the first to define and discuss the concept of strategy in game theory. During the Second World War, as a Jew he was compelled to hide from persecution by the Nazis, yet continued his mathematical work despite great hardship. In 1944, Steinhaus proposed the problem of dividing a cake into n pieces so that it is proportional and envy free (see cake-cutting). He is also well known as the author of the widely-read Mathematical Snapshots.