This paper summarizes logical investigations in Poland in the years 1945–1975 conducted by logicians living and working in the country. We concentrate on mathematical logic and the foundations of mathematics. Thus, we omit works in semantics (except logical model theory) and methodology of science; that is, other branches of general logic (logic sensu largo). We also skip investigations into the history of logic, one of the favorites of Polish logicians, except for mentioning reconstructions of some earlier systems. We also try to outline sociological circumstances relevant for the development of logic after the Second World War.