The Nencki Institute in Warsaw was founded in 1918 to honor one of Poland's most distinguished biochemists, Marceli Nencki. Since its inception, the institute has evolved from a confederation of privately supported laboratories to a center of research productivity intimately associated with the Polish Academy of Sciences. Early relations with Pavlov's laboratory laid the foundation for the emergence of a Polish School of Neurophysiology under the leadership of Jersy Konorski. The impact of Konorski and his colleagues has transformed the interpretation of conditioning to include a systematic physiologic basis that more adequately considers the psychology of learning processes. The prestige of the Nencki Institute within contemporary Eastern European and Soviet science was achieved despite the economic pressures on a new nation and its total devastation of World War II. Moreover, the more than 60 years of scientific work in an independent Poland have provided a critical transition between Eastern and Western research efforts, and the Nencki Institute has filled a leading role in facilitating communication among scientists.