An encyclopedia is a reference scientific publication that, in a concise form, sets out the totality of knowledge of all fields of science and important world events at a given time (general encyclopedia) or of a specific field of knowledge dedicated to one or several fields of science (specialized, sectoral) . Various types of articles can be included in the composition: short, detailed, overview, biographical, terminological, etc., systematized in alphabetical or thematic order. The name originates from the Greek concept ἐγκύκλιος παιδεία meaning “general education”.

Attempts to unify all human knowledge have been made since the earliest periods of written culture. In Western literature, the main components for the classification of knowledge were formed in ancient times: the trivium – grammar, logic, rhetoric; and the quadrivium – geometry, arithmetic, astronomy, music. The first exemplary encyclopedic works are the lost Disciplinarum libri IX (“Nine Books on the Sciences”) from the 2nd-1st centuries BC. of the Roman scientist Marcus Terentius Varro and Naturalis Historia (“Natural History”), compiled in the 1st century AD. by the Roman naturalist, philosopher and military leader Gaius Pliny the Elder. Pliny’s encyclopedia covers a wide range of subjects – history, geography, astronomy, pharmacy, botany, etc., and was used by compilers of reference literature until the end of the Middle Ages. Later medieval, thematically structured encyclopedic works such as Institutiones divinarum et saecularium litterarum (“Institutions of the Divine and Human Sciences”) of the 6th century Roman statesman and writer Cassiodorus assign an important place to Christian theology. The 7th-century Etymologarium sive originum libri XX (“20 Books of Origins or Etymologies”) of the Spanish archbishop Saint Isidore of Seville, which accepted the liberal arts and secular learning as the foundation of Christian education, also included an alphabetical dictionary. Prose was established as the main form, but encyclopedias containing verse are also found, such as De nuptiis Philologiae et Mercurii (“The Wedding of Philology and Mercury”) of the 5th century Roman poet and writer Marcian Capella and L’image du monde ( “The Image of the World”) from the 13th century by the French poet and priest Gauthier de Metz.

Rich encyclopedic traditions developed independently in the East. China’s earliest encyclopedia, the Huanglan (皇覽, “Imperial Review”), commissioned by the emperor and completed in 222, is now lost, but a number of later works attest to it. A major feature of early Chinese encyclopedias is the use of direct quotations from the sources used. The sixth-century Yuan Leiju (藝文類聚, “Anthology of Arts and Literature in Categories”) set the standard for systematization. The most extensive encyclopedia in medieval China is the Yunlu Dadien (“Great Classical Compendium of the Yunlu Period”) from the 15th century, composed in 11,095 volumes, of which only a small number of copies have been preserved today. In the 9th century, the Islamic writer of Persian origin, Ibn Qutayba, compiled in Arabic the Kitab uyun al-akbar (كتاب عيون الاخبار, “Book of useful knowledge”) – an encyclopedic collection enriched with proverbs and examples from history and poetry on the topics of power , war, nobility of character, oratory, friendship and women. The Persian mathematician, astronomer and geographer Muhammad Al-Khwarizmi created the encyclopedia Mafatih al-ulum (مفاتيح العلوم, “Keys of Knowledge”) in the Persian language at the end of the 10th century. The book summarizes the knowledge of the Islamic world up to this period: its first part deals with law, jurisprudence, dialectic, prosody and history, the second with philosophy, logic, medicine, arithmetic, geometry, astronomy, music and mechanics. In Southeast India in the 12th century, the Sanskrit encyclopedic work Manasollasa (मानसोल्लास, “Delight of the Mind”) was created on a wide range of topics, such as politics, ethics, economics, astronomy, astrology, rhetoric, architecture, veterinary medicine, cookery, games , fine arts, dance and music.

One of the most remarkable and imposing works of medieval encyclopedic literature is the 13th-century Speculum maius (“Great Mirror”) by the French monk Vincent de Beauvais. Divided into 80 books, the collection draws information from thousands of not only Latin, but also Greek, Arabic and Hebrew sources. In Encyclopaediæ, seu orbis disciplinarum, tam sacrarum quam prophanarum, epistemon (“Encyclopaedia, or knowledge of the world of disciplines, both sacred and secular”), published in 1559, the Croatian-born German writer and compiler Pavao Skalic first once used the term “encyclopedia” in the title of such a work. Instuario magna (“The Great Renewal”) of 1620 by the English jurist and philosopher Francis Bacon, Encyclopaedia, Septem Tomis Distincta (“Encyclopedia divided into seven volumes”) of 1630 by the German theologian and pedagogue Johann Heinrich Alstedt, Dictionnaire Historique et Critique (“Historical and Critical Dictionary”) of 1697 by the French philosopher and lexicographer Pierre Bayle and other 17th-century encyclopedias reflected the new ideas of the Enlightenment—encouraging intellectual freedom and the scientific approach and establishing a systematic classification of human knowledge that did not founded on religion and paved the way for rational thought. In compiling the Lexicon Technicum (“Technical Lexicon”), published in 1704, the English scholar and theologian John Harris was one of the first to use the paid help of experts. English encyclopedist Ephraim Chambers’s 1728 Cyclopædia or Universal Dictionary of Arts and Sciences was innovative in its clarity, easy reference system, and numerous illustrations. German bookseller and publisher Johann Heinrich Zedler’s massive Grosses completes Universal-Lexicon aller Wissenschafften und Künste (“Great Comprehensive Lexicon of All Sciences and Arts”) of 1732–1750 covers both the humanities and natural sciences, as well as biographies of prominent individuals.

The most ambitious and influential encyclopedia was the Encyclopédie, Ou Dictionnaire Raisonné Des Sciences, Des Arts Et Des Métiers (“Encyclopedia, or Interpretive Dictionary of the Sciences, Arts, and Crafts”) of 1751–1780, compiled under the direction of the French enlightener Denis Diderot and Jean le Rhône d’Alembert featuring Charles Louis de Montesquieu, Voltaire, Jean-Jacques Rousseau and others. The 35-volume work occupies a central place in shaping the modern appearance of encyclopedias and in spreading the ideals of rationality, tolerance and progress. In the 18th and 19th centuries, encyclopedic institutions were born, whose tradition continues to this day: the English Encyclopaedia Britannica (“Encyclopedia Britannica”) with the first edition from 1768-1771, the German Brockhaus Enzyklopädie (“Brockhaus Encyclopedia”) with the first edition – 1796–1808, Encyclopedia Americana (“American Encyclopedia”) – 1829–1833, the French Grand Larousse dictionnaire universel (“Grand Universal Dictionary of Larousse”) – 1866–1876, etc. Following their model, encyclopedias were created in other countries in the 19th and 20th centuries: Encyklopedia Powszechna (“Universal Encyclopedia”, Poland) from 1858–1868, Egyetemes magyar encyclopaedia (“Universal Hungarian Encyclopedia”) from 1861–1876. , Koji Ruyen (古事類苑, “Encyclopedia of Ancient Matters”, Japan) from 1896–1914, Enciclopedia universal ilustrada europeo-americana (“Universal Illustrated European-American Encyclopedia”, Spain) from 1905–1933, Enciclopedia Italiana di Scienze, Lettere e Arti (“Italian Encyclopedia of Sciences, Literature and Arts”) from 1929–1936, Bolshaya Sovetskaya Encyclopedia (“Great Soviet Encyclopedia”, Russia) from 1926–1947, etc. The encyclopedias of this period included a system of references and indexes, illustrations, geographical maps, and reference books. They are updated through new editions, additions and yearbooks under the guidance of a permanent editorial team and with the help of scientific consultants and article authors. International collaborations are formed. Numerous specialized and biographical encyclopedias, as well as encyclopedias for children, are being created.

With the development of digital technologies in the 21st century, the appearance of encyclopedias is changing. Many provide digital editions or free online access, reaching a much wider audience. Language translations, video and audio files and interactive maps are incorporated. Encyclopaedias such as Wikipedia (Wikipedia) with open access for users to generate, modify and maintain online articles are widely used, but do not guarantee the quality, objectivity and comprehensiveness of the information provided or the authority of the sources used. The new dynamic environment requires encyclopedia compilers to adapt quickly, update promptly, and check even more rigorously for accuracy and authenticity of facts in the mission to preserve, share, and understand human knowledge.