The book, based on documents from Ukrainian, German, Polish and other archives, memoirs of participants in events and scientific literature, studied the reasons and circumstances of the detention and executions of representatives of the Polish intelligentsia by Hitler's security forces at the beginning of World War II. The process of investigating the murders was highlighted and the Nazi war criminals involved in their commission were named, namely the customers, organizers and perpetrators of these crimes. Refuted as a groundless official version of the State Security Committee of the Soviet Union on the complicity of the servicemen of the Nachtigal battalion in the executions of Polish scientists. The main reasons are explained and the technology of creating and using this myth as an integral element of a large-scale propaganda campaign organized in the USSR for political purposes since the early 1960s is revealed. For scientists, students and anyone interested in the history of World War II.