An incoming mobility fellowship from NAWA, the Polish National Agency for Academic Exchange, that brings researchers from abroad to Polish universities and research institutes for stays of between six and twenty-four months. It is open to anyone holding at least a doctoral degree, from any country and in any field of science, with a monthly scholarship plus a mobility allowance toward travel; a small quota is reserved for Polish scientists working permanently abroad. Fellows join the host institution's research projects and teaching rather than working in isolation, so it functions as a genuine placement rather than a visiting stipend. Named for the mathematician Stanislaw Ulam. The mirror scheme for outgoing Polish researchers is NAWA's Bekker Programme.