encyclopedia, compendium of knowledge, either general (attempting to cover all fields) or specialized (aiming to be comprehensive in a particular field).
Encyclopedias and Other Reference Books
Basically an encyclopedia differs from a dictionary in that a dictionary is fundamentally devoted to words and an encyclopedia offers information on various subjects, with data on and discussion of each subject identified. An almanac differs from an encyclopedia in that an almanac normally is issued periodically and includes ephemeral data applicable at the time of issue, while an encyclopedia is assembled from accumulated knowledge within a broader scope. An atlas is devoted to maps and charts.
Attempts at encompassing universal knowledge began with the brilliantly comprehensive works of Aristotle. Other classical writers tried to follow his example, and the Natural History of Pliny the Elder is sometimes called the first encyclopedia. Alexandrian scholars did some work of an encyclopedic nature in compiling their lengthy anthologies and summations of knowledge. The Asian encyclopedias, particularly the voluminous Chinese collections, were actually more in the nature of anthologies than reference works. In the Middle Ages various scholars drew up compendiums of knowledge; notable were the Etymologiae of Isidore of Seville, a curious mixture of fact and legend, and 13th-century works by Vincent of Beauvais, Roger Bacon, and Brunetto Latini.
The modern type of encyclopedia—with alphabetical arrangement and frequently with bibliographies—is usually said to have been established by John Harris in his Lexicon technicum (1704). Perhaps the most renowned of all encyclopedias, the Encyclopédie, was completed in 1772 by Diderot and others in France. The first edition of the Encyclopaedia Britannica was published in three volumes (1768–71). It grew in size (to 32 volumes) and reputation over the years; despite its name, the encyclopedia has long been edited and published in the United States. In 2012 it announced that its 2010 printing of the 15th edition would be its last print edition.
The oldest German encyclopedia still being published is Brockhaus' Konversations-Lexikon, first issued from 1796 to 1808. On this, rather than on Ephraim Chambers's Cyclopaedia (1st ed. 1728), was based the British Chambers's Encyclopedia (1st ed. 1859–68). The famous Larousse Grand Dictionnaire universel du XIXème siècle français in 17 volumes was published from 1865 to 1888. The 30-volume Saudi Global Arabic Encyclopedia, the first modern encyclopedia in Arabic and with an Arab perspective, was published in 1997.
The first noteworthy American encyclopedia was The Encyclopedia Americana, edited by Francis Lieber (13 vol., 1829–33). Important American encyclopedias include Collier's Encyclopedia (24 vol., 1949–51) and Encyclopedia International (20 vol., 1963). Notable multivolume juvenile encyclopedias are The Book of Knowledge (1910), World Book Encyclopedia (1917), Britannica Junior (1934), Compton's Pictured Encyclopedia (1922), and Merit Students Encyclopedia (1967).
Since the advent of computer technology, encyclopedias have been made available in CD-ROM format (see compact disc), sometimes as part of a reference package; and as part of an on-line service. CD-ROM encyclopedias, which have been largely been superseded by on-line ones, offered multimedia enhancements, such as video and sound clips and animated illustrations; on-line encyclopedias especially are easily and frequently updated. All electronic encyclopedias make use of hypertext cross-references. Another product of the computer age is the Wikipedia, an Internet-based on-line encyclopedia (est. 2001) sponsored by a nonprofit corporation and written and edited collaboratively by volunteers (anyone may submit articles, additions, or corrections).
Some specialized encyclopedias are in many volumes, such as the Encyclopedia of Philosophy, the International Encyclopedia of the Social Sciences, the Encyclopedia of Islam, and the New Grove Dictionary of Music. Most specialized encyclopedias, however, are one volume or two. The one-volume general encyclopedia became popular in Europe early in the 20th cent., but the first comprehensive one-volume general encyclopedia in English was The Columbia Encyclopedia (1935), now in its sixth edition. A number of compact desk encyclopedias are also now available.
See E. P. Sheehy, Guide to Reference Books (annual supplement); R. L. Collison, Encyclopaedias: Their History throughout the Ages (2d ed. 1966); K. F. Kister, Kister's Best Encyclopedias (2d ed. 1994).