"Big Soviet Encyclopedia" is the largest Soviet encyclopedia, which was published in Moscow between 1926 and 1990. In its 65 volumes, it combined information from various fields of knowledge: from history and politics to science and technology. The encyclopedia was created for the purpose of education, enlightenment and promotion of the development of a socialist society. In its pages, the reader can find substantiated articles about prominent cultural figures, scientific discoveries, geographical objects, animal and plant life, various production processes, and much more. The "Great Soviet Encyclopedia" was an important source of knowledge for a wide audience, including schoolchildren, students, scientists and people just curious about the world. This encyclopedia reflected the ideology and spirit of the era, its materials were important for the formation of the worldview and cultural heritage of generations during the existence of the Soviet Union. "Great Soviet Encyclopedia" remains a significant standard of world popular science literature of the last century.