History of the Encyclopædia Britannica the criteria by which the articles were sorted were not obvious even to scholars, despite Dr. Adler's claims that the sorting followed naturally from the "Propædia's" outline of all knowledge. In 1985, the "Britannica" responded to reader requests by restoring the index as a two-volume set. The number of topics indexed by the "Britannica" has fluctuated from 500,000 (1985, the same as in 1954) to 400,000 (1989,1991) to 700,000 in the current 2007 print version. Presumably, this recent increase reflects the introduction of efficient electronic indexing, since the size of the encyclopedia has remained nearly constant at approximately 40 million
Encyclopædia Britannica First Edition 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 6 December 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. By releasing the numbers in weekly installments, the "Britannica" was completed in 1771, having 2,391 pages. The numbers were bound in three equally sized volumes covering Aa–Bzo, Caaba–Lythrum, and Macao–Zyglophyllum; an estimated