The article considers an example from the history of Soviet science of the 1940s within the framework of the definition of scientific leadership as a research activity involving, firstly, the cognitive influence of the scientist on the academic community, and, secondly, his ability to use rational mechanisms to implement the initiated scientific ideas. The emphasis is made on the second part of the definition identifying personal qualities, mechanisms, and tools that determined the managerial effectiveness of the scientific leader (I. A. Efremov) in specific social contexts. It is shown that in order to approve his expeditions I. A. Efremov had to overcome internal-academic, and external-state administrative and bureaucratic barriers. The success of his organizational activities was determined by personal qualities, his scientific authority, knowledge of the structure of public administration of science, and his communication networks as well. During his first expedition, he ventured change the route, something which became the main factor of its scientific effectiveness and further success in Mongolia. At the stage of organizing the expedition, I. A. Efremov showed himself as an succesful manager of the scientific project, and when choosing a route - as a scientist, capable of producing extraordinary ideas and taking responsibility for their realization. While before the Mongolian expeditions I. A. Efremov was considered as a distinguished scientist and an outstanding expert in his field of knowledge, after the results of Mongolian expeditions he became a recognized scientific leader in the field of vertebrate paleontology. At the same time, this recognition did not affect the advancement of his scientific career inside the USSR Academy of Sciences.
