Encyclopædia Britannica

The is a general knowledge English-language encyclopaedia. It has been published by Encyclopædia Britannica, Inc. since 1768, although the company has changed ownership seven times. 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.

Printed for 244 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 three volumes. The encyclopaedia grew in size; the second edition was 10 volumes, and by its fourth edition (1801–1810), it had expanded to 20 volumes. Its rising stature as a 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.

In 1933, the ''Britannica'' became the first encyclopaedia to adopt "continuous revision", in which the encyclopaedia is continually reprinted, with every article updated on a schedule. In the 21st century, the ''Britannica'' suffered first from competition with the digital multimedia encyclopaedia Microsoft Encarta, and later with the online peer-produced encyclopaedia Wikipedia.

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

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. Over 70 years, the size of the ''Britannica'' has remained steady, with about 40 million words on half a million topics. Though published in the United States since 1901, the ''Britannica'' has for the most part maintained British English spelling. Provided by Wikipedia