The Encyclopædia Britannica has been published continuously since 1768, appearing in 15 official editions. Several editions have been amended with multi-volume "supplements" (3rd-6th) or undergone drastic re-organizations (15th). In recent years, digital versions of the Britannica have been developed, both online and on optical media. Since the early 1930s, the Britannica has developed several "spin-off" products to leverage its reputation as a reliable reference work and educational tool.

Historical context

Earliest editions (1st-6th, 1768-1824)
The Britannica was the idea of Colin Macfarquhar, a bookseller and printer, and Andrew Bell, an engraver, both of Edinburgh. They conceived of the Britannica as a conservative reaction to the French Encyclopédie of Denis Diderot (published 1751-1766), which was widely viewed as heretical. Ironically, the Encyclopédie had begun as a French translation of the popular English encyclopedia, Cyclopaedia published by Ephraim Chambers in 1728. Although later editions of Chambers' Cyclopaedia were still popular, and despite the commercial failure of other English encyclopedias, Macfarquhar and Bell were inspired by the intellectual ferment of the Scottish Enlightenment and thought the time ripe for a new encyclopedia "compiled upon a new plan".
Needing an editor, the two chose a 28-year-old scholar named William Smellie who was offered 200 pounds sterling to produce the encyclopedia in 100 parts (called "numbers" and equivalent to thick pamphlets), which were later bound into three volumes. The first number appeared on December 6 1768 in Edinburgh, priced sixpence or 8 pence on finer paper. The Britannica was published under the pseudonym "A Society of Gentlemen in Scotland", possibly referring to the many gentlemen who had bought subscriptions.

1st edition
After the success of the first edition, a more ambitious second edition was begun in 1776, with the addition of history and biography articles. Conversely, the 2nd edition describes the architecture of Noah's Ark in detail (illustrated with a copperplate engraving) and, following Bishop Ussher, includes a remarkably precise chronology for the Earth, beginning with its creation on 23 October 4004 B.C. and noting that the Great Flood of 2348 B.C. lasted for exactly 777 days. The 2nd edition also reports a cure for tuberculosis
and a somewhat melancholy article on "Love" that persisted in the Britannica for nearly a century (until its 9th edition)

2nd edition
The third edition was published from 1788 to 1797 in 300 weekly numbers (1 shilling apiece); these numbers were collected and bound in 30 parts (10 shilling, sixpence each) and finally in 18 volumes with 14,579 pages and 542 plates. Macfarquhar again edited this edition up to "Mysteries" but died in 1793 (aged 48) of "mental exhaustion"; his work was taken over by George Gleig, later Bishop Gleig of Brechin (consecrated 30 October 1808). Andrew Bell, Macfarquhar's partner, bought the rights to the Britannica from his heirs.
Nearly doubling the scope of the 2nd edition, Macfarquhar's encyclopedic vision was finally realized. Recruited by Gleig, several illustrious authorities contributed to this edition, such as Dr. Thomas Thomson, who introduced the first usage of chemical symbols, and John Robinson, Secretary of the Royal Society of Edinburgh, who wrote several well-regarded articles on natural philosophy. The third edition established the foundation of the Britannica as an important and definitive reference work for much of the next century. This edition was also enormously profitable, yielding 42,000 pounds sterling profit on the sale of roughly 10,000 copies. The 3rd edition began the tradition (continued to this day) of dedicating the Britannica to the reigning British monarch, then King George III; calling him "the Father of Your People, and enlightened Patron of Arts, Sciences and Literature", Gleig wished
The 3rd edition is also famous for its bold article on "Motion", which categorically rejects Isaac Newton's theory of gravitation. Instead, Dr. Gleig wrote that gravity is caused by the classical element of fire. He seems to have been swayed by William Jones' Essay on the First Principles of Natural Philosophy (1762), which in turn was based on John Hutchinson's MA thesis, Moses' Principia, which was written in 1724 but rejected by Oxford University. Nevertheless, Gleig was sanguine about the errors of the 3rd edition, echoing William Smellie's sentiment in the 1st edition quoted above
The first "American" encyclopedia, Dobson's Encyclopædia, was based almost entirely on the 3rd edition of the Britannica and published at nearly the same time (1788-1798), together with an analogous supplement (1803), by the Scottish-born printer, Thomas Dobson. The first United States copyright law was passed on 30 May 1790 — although anticipated by Section 8 of Article I of the United States Constitution (ratified 4 March 1789) — but did not protect foreign publications such as the Britannica. Piracy of the Britannica in America remained a problem through the 9th edition (1889). Pirated copies were also sold in Dublin by James Moore under the title, Moore's Dublin Edition, Encyclopædia Britannica; this was an exact reproduction of the Britannica's 3rd edition. Nineteenth-century editions of the Britannica regularly included high-level research works from its authors; by contrast, the 20th century editions are notable for being more popularized, easier to understand but less scholarly.

3rd edition
A two-volume supplement to the 3rd edition was published in 1801, having 1,624 pages and 50 copperplates by D. Lizars. This supplement was published by a wine-merchant, Thomas Bonar, the son-in-law of the Britannica's owner Andrew Bell; unfortunately, the two men quarreled and they never spoke for the last ten years of Bell's life (1799-1809).
The Britannica explicitly positioned itself as a conservative publication in reaction to the radical French Encyclopédie of Diderot published between 1751-66. In the royal dedication penned on 10 December 1800, Dr. Gleig elaborated on the editorial purpose of the Britannica

Supplement to the 3rd edition
The 4th edition was begun in 1800 and completed in 1810, comprising 20 volumes with 16,033 pages and 531 plates engraved by Andrew Bell. The editor was Dr. James Millar, a physician, who was good at scientific topics but criticized for being "slow & dilatory & not well qualified". The mathematical articles of Prof. Wallace were widely praised in the 4th edition but, overall, the 4th edition was a minor revision of the 3rd, updated in its historical and biographical articles.
The copyright of the material in the supplement to the 3rd edition was owned by Thomas Bonar, who asked 20,000 pounds sterling for it. The supplemental material was licensed for the fourth edition for 100 pounds, but this copyright issue remained a problem through the 5th edition.
Bonar was friendly to the article authors, however, and conceived the plan of paying them as well as the article reviewers, and of allowing them to retain copyright for separate publication of their work.

4th edition
After Andrew Bell died in 1809, his heirs botched the fifth edition; the dilatory and unqualified Dr. Millar was again the editor. Completed in 1817, the fifth edition sold for 36 pounds sterling and consisted of 20 volumes with 16,017 pages and 582 plates. The fifth edition was a relatively minor revision of the fourth, which in turn was a relatively minor revision of the 3rd edition and its supplement.

5th edition
After securing sole-ownership rights in December 1816, Constable began work on a supplement to the 5th edition, even before the 5th edition had been released (1817). The supplement was completed in April 1824, consisting of 6 volumes with 4933 pages, 125 plates, 9 maps, 3 "dissertations" and 160 biographies, mainly of people who had died within the preceding 30 years. This edition was the first to have an Index listing the 669 articles.
This supplement had remarkably illustrious contributors. Constable was friends with Sir Walter Scott, who contributed the "Chivalry" article. To edit the supplement, Constable hired Macvey Napier, who recruited other eminent contributors such as Sir Humphry Davy, Jean-Baptiste Biot, John Stuart Mill, William Hazlitt, David Ricardo, and Thomas Malthus. Thomas Young's article on Egypt included the translation of the hieroglyphics on the Rosetta Stone.

Supplement to the 5th edition
Constable also produced the 6th edition, which was completed in May 1823. It was published in 40 half-volume parts, priced 16 shillings in boards. The editor was Charles Maclaren. Unfortunately, Constable went bankrupt on 19 January 1826 and the rights to the Britannica were sold on auction; they were eventually bought on 16 July 1828 for 6150 pounds sterling by a partnership of four men: Adam Black (a publisher), Alexander Wight (a banker), Abram Thomson (a bookbinder) and Thomas Allen, the proprietor of the Caledonian Mercury. Not long after, Black bought out his partners and ownership of the Britannica passed to the Edinburgh publishing firm of A & C Black.

6th edition

A. and C. Black editions (7th-9th, 1827-1901)
The 7th edition was begun in 1827 and published from March 1830-January 1842. It was edited by Macvey Napier, who was assisted by James Browne, LLD. It consisted of 21 volumes with 17,101 pages and 506 plates, with an Index of 187 pages. This was the first edition to include a general index for all articles, a practice that was maintained until 1974.
Many illustrious contributors were recruited to this edition, including Sir David Brewster, Thomas de Quincey, Antonio Panizzi and Robert Stephenson. James Wilson did all of zoology, Dr. Hampden did all of Greek philosophy, and William Hosking contributed an excellent article on architecture. Mathematical diagrams were made from woodcuts.
The 7th edition went on sale for £24 per set. However, Adam Black had invested over £108,766 in its production: £5,354 for advertising, £8,755 for editing, £13,887 for 167 contributors, £13,159 for plates, £29,279 for paper, and £19,813 for the printing. In the end, roughly 5,000 sets were sold but Black considered himself well-rewarded in intellectual prestige.

7th edition
The 8th edition was published from 1853-1860 in 21 volumes, with 17,957 pages and 402 plates and a 239-page Index (published separately in 1861). Since Macvey Napier died in 1847, Adam Black selected for its editor Dr. Thomas Stewart Traill, a professor of medical juriprudence at Edinburgh University. When Dr. Traill fell ill, he was assisted by a young Scottish philosopher, John Downes. Black was able to hold costs to roughly £75,655. This edition began the tradition of a contributors' banquet to celebrate the edition's completion (5 June 1861).

8th edition
The landmark ninth edition, often called 'the Scholar's Edition',

9th edition, The Scholar's Edition

First American editions (10th-14th, 1901-1973)
Again under the sponsorship of The Times of London, the new owners quickly produced an 11-volume supplement to the 9th edition; the editors were Hugh Chisholm, Sir Donald Mackenzie Wallace, Arthur T. Hadley and Franklin Henry Hooper, the brother of the owner Horace Hooper. Taken together, the 35 volumes were dubbed the "10th edition". The re-issue of the 9th edition under the moniker "10th edition" caused some outrage, since many articles of the 9th edition were over 25 years old, and beginning to show their age. This led to the popular joke: "The Times is behind the Encyclopædia Britannica and the Encyclopædia Britannica is behind the times."

10th edition (supplement to the 9th)
The renowned 11th edition of Encyclopædia Britannica was begun in 1903, and published in 1910-1911 in 28 volumes, with a one-volume Index. Edited by Hugh Chisholm in London and by Franklin Hooper in New York, the 11th edition was the first to be published substantially at one time, instead of volume by volume. Its illustrious contributors are legion, including Baden-Powell writing on kite-flying; Arthur Eddington on astronomy; Edmund Gosse on literature and Donald Tovey on music. Sometimes called the 1911 Encyclopædia Britannica, this edition is still highly regarded for its lucid explanations of scholarly subjects. Being in the public domain, the complete text is freely available online.

11th edition
The poor sales of the war years brought the Britannica to the brink of bankruptcy. Luckily, the CEO of Sears Roebuck, philanthropist Julius Rosenwald, was devoted to the mission of the Britannica and bought its rights on 24 February 1920 from his friend Horace Everett Hooper for $1.25 million dollars. The Britannica's headquarters were moved to Chicago, where they have remained ever since. In 1922, a 3-volume supplement to the 11th edition was released that summarized the developments just before, during and after World War I; these three volumes, taken together with the 11th edition, became known as the 12th edition. Horace Hooper died in 1922, a few weeks after the publication of the 12th edition. This edition was a commercial failure, losing Sears roughly $1.75 million dollars, after which Sears gave it back to Hooper's widow, Harriett Meeker Cox, and her brother, William J. Cox, who ran the company from 1923-1928.
The passage of a few years led to a better perspective on that era. In 1926, the Britannica released three new volumes covering the history of 1910-1926, which were intended to supplant those of the 12th edition. Again taken together with the 11th edition, the new volumes became known as the 13th edition, which maintained the Britannica's tradition of illustrious contributors: Harry Houdini, Albert Einstein, Marie Curie, Sigmund Freud, Henry Ford, Leon Trotsky, Ferdinand Foch, Gustav Stresemann, Thomas G. Masaryk and Elihu Root.
In 1928, Rosenwald bought back the rights to the Britannica, leaving Cox as publisher. Cox argued forcefully for a new 14th edition, pointing out that the 11th edition (the bulk of the 12 and 13th editions) was badly out of date. Cox also tried to involve the University of Chicago in producing the Britannica, even including a $1 million advance from Rosenwald as a temptation; however, the trustees of the University turned down his proposal, a choice they almost repeated a generation later under William Benton.

12th and 13th editions (competing supplements to the 11th)
By 1926, the 11th edition was beginning to show its age, and work on a new edition was begun. The editors were J. L. Garvin in London and Franklin Henry Hooper in New York. The 14th edition took three years to complete, at the then exhorbitant cost of $2.5 million dollars, all of it invested by Julius Rosenwald of Sears, Roebuck and Company. It was very different to the 11th edition, having fewer volumes and simpler articles, continuing the business strategy of popularizing the Britannica for the American mass market at the expense of its scholarship.
The 14th edition was published in September 1929, and had 23 volumes with a one-volume Index that also contained a complete atlas. Unfortunately, the Great Depression struck scarcely a month after the release of the 14th edition, and sales plummeted. Despite the unfailing support of the Sears Roebuck company, the Britannica almost went bankrupt over the next few years. Rosenwald died in 1932, and General Robert E. Wood took over; Cox was removed as publisher and the Secretary-Treasurer of Sears, Elkan Harrison Powell was installed as the new President of the Britannica.

14th edition
E. H. Powell identified and fixed a key vulnerability of Britannnica, namely, that its sales (and, hence, the company's income) fluctuated strongly over the life-cycle of an edition. After the release of a new edition, sales would generally begin strong, and decline gradually for 10-20 years as the edition began to "show its age"; finally, sales would drop off precipitously with the announcement that work had begun on a new edition, since few people would buy an obsolete encyclopedia that would soon be updated. These strong fluctuations in sales led to economic hardship for the Britannica.
To amend this problem, Powell suggested in 1933 the policy of continuous revision, with the goal of keeping the Britannica "always timely and always salable". The basic idea was to maintain a continuous editorial staff that would constantly revise the articles on a fixed schedule. Earlier encyclopedias did not maintain a continuous editorial staff, but rather assembled one just prior to beginning a new edition. Rather than releasing supplemental editions or volumes, new printings would be made every year with only enough copies made to cover the sales for that year. An analysis of the Britannica's articles suggested that roughly 75% required only occasional revising, whereas 25% required revision every 1-3 years. The articles were therefore divided into 30 classifications and a schedule for their revision worked out, such that every article would be checked at least twice a decade.
Powell also conceived the Britannica's "Book of the Year", in which a single volume would be released every year covering the developments of the previous year, particularly in rapidly changing fields such as science, technology, culture and politics. The "Book of the Year" continues to be published even today. Powell also introduced the Library Research Service (1936), in which owners of the Britannica could write to have their personal questions researched and answered by the editorial staff.
Under Powell's leadership, the Britannica began to capitalize on its reputation by aggressively developing "spin-offs", such as the 12-volume Britannica Junior for children (published 1934, and revised to 15 volumes in 1947), the historical timeline The March of Man (published 1935, and edited by Albert Bushwell Hart, Isaac J. Cox and Lawrence H. Dawson), the Encyclopædia Britannica World Atlas (published 1942, and prepared by G. Donald Hudson) and Ten Eventful Years, a summary of the national and international events surrounding World War II (1937-1946).

Policy of continuous revision
Sears Roebuck published the Britannica until 1943. In 1941, Sears offered the rights to the Britannica as a gift to the University of Chicago. The story of this offer was recounted at the bicentennial banquet of the Encyclopædia Britannica
"Yes," replied General Wood, "Sears, Roebuck should never have acquired it in the first place."
"Does it make any money?" Bill asked. Wood replied that sales would earn his company some $300,000 before taxes that year. Bill replied, "Well, General, you know that universities do not have any money. They cannot buy businesses. Why don't you make a gift of the Britannica to the University of Chicago?"
General Wood did not reply immediately but walked to his car. As he got into the car, he turned to Bill Benton and said, "All right, Bill, I will give you the Britannica."
The University of Chicago declined the offer, viewing the mission of the university as not entirely consistent with a large commercial publishing house; however it continues even today to be involved in its production, offering editorical advice and allowing its name to be associated with the Britannica. Thus, in 1943, the wealthy and powerful William Benton, a former U.S. senator and advertising executive, obtained exclusive control of the Britannica, which he published until his death in 1973. His widow Helen Hemingway Benton continued to publish the Britannica until her own death in 1974. After their deaths, the Benton Foundation continued to manage the Britannica until it was sold to Jacqui Safra in 1996.

The current 15th edition
Despite the policy of continuous revision, the 14th edition of the Britannica gradually became outdated, much as its predecessors, the 9th and 11th editions. Beginning in the early 1960s, the failings of the 14th edition began to be collated and published by physicist Harvey Einbinder, culminating in his highly critical 390-page book, The Myth of Britannica (1964). Goaded into action, the Britannica began to work on a new edition, the current 15th.
The 15th edition was produced over ten years at a cost of $32 million dollars and released in 1974 in 30 volumes. The so-called New Encyclopædia Britannica (or Britannica 3) had a unique three-part organization: a single Propædia (Primer for Education) volume, which aimed to provide an outline of all known, indeed knowable, information; a 10-volume Micropædia (Small Education) of 102,214 short articles (strictly less than 750 words); and a 19-volume Macropædia (Large Education) of 4,207 longer, scholarly articles with references, similar to those of the 9th and 11th editions. despite Dr. Adler's claims that the sorting followed naturally from the Propædia's outline of all knowedge.

Second version (1985-present)
In the 1980s, Microsoft approached Britannica Inc. to collaborate on a CD-ROM encyclopedia, but the offer was declined. The senior managers at Britannica were confident in their control of the market and that their healthy profits would continue. At this time complete sets of the encyclopedia were priced between $1,500 and $2,200, and the product was considered part of a luxury brand with an impeccable reputation handed down from generation to generation. The management did not believe that a CD-ROM could adequately compete or supplement their business. In turn, Microsoft used content from Funk & Wagnalls Standard Encyclopedia to create what is now known as Encarta.