Encyclopædia Britannica

The is a general-knowledge English-language encyclopaedia. It has been published since 1768, and after several ownership changes is currently owned by Encyclopædia Britannica, Inc. The 2010 version of the 15th edition, which spans 32 volumes and 32,640 pages, was the last printed edition. Since 2016, it has been published exclusively as an online encyclopaedia at the website Britannica.com.

Printed for 245 years, the ''Britannica'' was the longest-running in-print encyclopaedia in the English language. It was first published between 1768 and 1771 in Edinburgh, Scotland, in weekly instalments that came together to form three volumes. At first, the encyclopaedia, from edition to edition, grew quickly in size. The second edition extended to 10 volumes, and by its fourth edition (1801–1810), the ''Britannica'' had expanded to 20 volumes. Since the beginning of the twentieth century, its size (at least in terms of total word length) has remained roughly steady, at about 40 million words.

The ''Britannica'' rising stature as an authoritative and scholarly work helped recruit eminent contributors, and the 9th (1875–1889) and 11th editions (1911) are landmark encyclopaedias for scholarship and literary style. Starting with the 11th edition and following its acquisition by an American firm, the ''Britannica'' shortened and simplified articles to broaden its appeal to the North American market. Though published in the United States since 1901, the ''Britannica'' has for the most part maintained British English spelling.

In 1932, the ''Britannica'' adopted a policy of "continuous revision," in which the encyclopaedia is continually revised and reprinted, with every article updated on a schedule. The publishers of ''Compton's Pictured Encyclopedia'' had already pioneered such a policy.

The 15th edition (1974–2010) has a three-part structure: a 12-volume of short articles (generally fewer than 750 words), a 17-volume of long articles (two to 310 pages), and a single volume to give a hierarchical outline of knowledge. The was meant for quick fact-checking and as a guide to the ; readers are advised to study the outline to understand a subject's context and to find more detailed articles.

In the 21st century, the ''Britannica'' faced strong competition: in particular from the digital and multimedia encyclopaedia Microsoft ''Encarta'', and later from the online peer-produced encyclopaedia Wikipedia. Despite (or perhaps because of) such competition, Britannica retained its reputation for authoritative, comprehensive, structured, and scholarly treatments of included subjects. While it continued to score well in assessments of its overall quality, as compared to its competitors, it could not (as an expert-authored compilation of a limited number of articles on only important subjects), match their breadth of coverage and continuous updating.

In March 2012, it announced it would no longer publish printed editions and would focus instead on the online version. Provided by Wikipedia