The article describes and analyses scientific and organizational activities of Otakar Nahodil at the Faculty of Arts, Charles University, within the wider context of Czech ethnography and folkloristics in the 1940-1960s. Based on the study of sources that have never been used for this theme to date and that originate in the management of the Faculty of Arts Charles University, the Communist Party of Czechoslovakia and various security forces, it was possible to trace the Nahodil´s way to the position of a probably most influential eminent authority in the ethnological science at that time, as well as his subsequent steep power fall. The study points to a lot of extraordinary problematic features of Nahodil´s research work and personality, which - within specific contexts of that period (ongoing marxization, or stalinization of scientific research and transformation in its themes, cleansing and settling of personal scores at the Faculty of Arts, Charles University, development of
the study of extra-European territories under the monitoring of intelligent services etc.) - strongly influenced the direction of Czech ethnology at that time.