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 2010, Encyclopædia Britannica, Inc. announced a partnership with mobile phone development company Concentric Sky to launch a series of iPhone products aimed at the K-12 market. On 20 July 2011, Encyclopædia Britannica, Inc. announced that Concentric Sky had ported the Britannica Kids product line to Intel's Intel Atom-based Netbooks and on 26 October 2011 that it had launched its encyclopedia as an iPad app. In 2010, Britannica released Britannica ImageQuest, a database of images. In March 2012, it was announced that the company would cease printing the encyclopaedia set, and that it would focus more on its online version. On