"Great Soviet Encyclopedia" (abbreviated KO) is the world's largest general scientific encyclopedia, published in the USSR in 1926-1990. In its 31 volumes, it covers almost all fields of knowledge, from natural sciences to literature, art and culture. Each volume of the encyclopedia contains hundreds of articles, illustrations and tables, which allows the reader to familiarize himself with any topic in detail. The "Great Soviet Encyclopedia" served as the main source of knowledge for millions of people in the former USSR and beyond. It became an important symbol of culture and education of that time, uniting generations in search of knowledge and discoveries. This encyclopedia is an important document in the history of science and culture, and an extremely valuable source of information for anyone interested in scientific research and general erudition.