Encyclopedia means "circle of knowledge"; these are books containing scientific information about natural phenomena and social life selected in a certain system. Encyclopedias summarize what people know about nature, peoples, economy, science, technology, culture and art. In encyclopedias, you can learn how people conquer and remake nature, how they grow bread and cotton, make paper, smelt cast iron and steel; they contain information about electric locomotives, motor ships, airplanes and the metro, about photography and cinematography, telegraph, radio, television, insects, birds, fish and animals, plants and minerals, planets and stars, about scientists, travelers, politicians, generals, writers, artists, artists, athletes and much, much more. This information is collected so much that it does not fit into one book, and encyclopedias usually consist of many volumes. The encyclopedia is richly illustrated, it presents digital tables, chronological data, etc. Volume 4 "Plants and Animals" - tells about the biological sciences that study the life of plants, animals and microorganisms. One of the sections of the book is devoted to outstanding biologists.