"Big Soviet Encyclopedia" (PS) is the most outstanding and complete Soviet encyclopedia, which was published in 1926-1990. In its 31 volumes, this encyclopedia contained a wide range of information from various fields of knowledge: from natural sciences to culture and art. More than 100,000 articles, accompanied by illustrations and maps, revealed all aspects of Soviet life. The Great Soviet Encyclopedia was an important source of knowledge for millions of people in the former Soviet Union. Due to its academicism and authority, it occupied a special place among the encyclopedias of the world. The publication of this encyclopedia was a great achievement of Soviet culture and science, which reflected the purpose and spirit of that time.