Encyclopedia

Encyclopedia

A bound encyclopedia volume
Type	Reference work
Purpose	Summarising knowledge across subjects
Earliest surviving	Naturalis Historia (c. AD 77)
Organisation	Usually alphabetical or thematic

An encyclopedia is a reference work that summarises knowledge, either across every field or within one. It differs from a dictionary in what it explains: a dictionary defines words, while an encyclopedia describes the things, people and ideas the words refer to. The word comes from the Greek enkyklios paideia, meaning something like "general education" — the circle of learning a person was expected to have.

Four features distinguish an encyclopedia from other kinds of book:

• Scope. A general encyclopedia covers everything at least briefly; a specialised one covers a single field in depth.
• Summary. Entries condense what is known rather than presenting new findings. An encyclopedia is a tertiary source, built on secondary sources, which in turn rest on primary evidence.
• Organisation. Alphabetical arrangement, now the norm, is a comparatively recent convention; earlier works were arranged thematically, following a scheme of how knowledge was thought to fit together.
• Method of access. Indexes, cross-references and, in a wiki, hyperlinks let a reader arrive at any entry directly instead of reading from the beginning.

Pliny the Elder's Naturalis Historia, completed around AD 77, is the oldest encyclopedic work to survive complete. It gathers some twenty thousand facts drawn from hundreds of earlier authors, on astronomy, geography, zoology, botany, medicine and mining, and set the pattern of the compiler who assembles rather than investigates. In the seventh century Isidore of Seville's Etymologiae organised knowledge by deriving it from the origins of words, and remained a standard reference for the better part of a thousand years.

Compilation traditions developed independently elsewhere. The Chinese leishu were vast classified compendia of quotations, culminating in the Yongle Encyclopedia of 1408, which ran to over eleven thousand volumes and was never printed.

The modern encyclopedia took shape in the eighteenth century. Ephraim Chambers's Cyclopaedia (1728) introduced systematic cross-references between articles, so that a reader could follow an idea across entries. Its most consequential effect was indirect: a proposed French translation grew, under Denis Diderot and Jean le Rond d'Alembert, into the Encyclopédie (1751–1772), twenty-eight volumes with over seventy thousand articles.

The Encyclopédie was more than a reference work. It treated crafts and trades as subjects worthy of the same careful description as theology, and used cross-references to place orthodox articles beside sceptical ones. It was suppressed, then tolerated, then imitated.^[1]

The Encyclopædia Britannica, first published in Edinburgh between 1768 and 1771, ran through fifteen editions and eventually became the best known English-language work of its kind. Its final printed edition appeared in 2010.

Digital publication removed the two constraints that had shaped every previous encyclopedia: the cost of paper and the need to fix the text at the moment of printing. CD-ROM encyclopedias of the 1990s undercut print sets on price. Online encyclopedias then removed the release cycle altogether, and collaborative ones removed the paid editorial staff as well — replacing prior review with public revision, on the argument that errors visible to everyone get fixed faster than errors visible to nobody.

Every encyclopedia is a secondhand account, and its accuracy depends on the sources it summarises and the care of its compilers. Printed encyclopedias were reviewed before publication but could not be corrected afterwards; a mistake persisted until the next edition, sometimes for decades. Collaboratively edited ones invert this: an error may appear at any moment, and may be corrected within minutes. Neither arrangement makes an encyclopedia a substitute for the sources it cites, which is why entries carry references.

• Wiki
• Library of Alexandria
• Printing press
• OpenWiki:About

1. ^ Darnton, Robert. The Business of Enlightenment: A Publishing History of the Encyclopédie. Harvard University Press, 1979.