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 June 7, 2018, Britannica released a Google Chrome extension, Britannica Insights, which shows snippets of information from Britannica Online in a sidebar for Google search results. The Britannica sidebar does not replace Google's sidebar and is instead placed above Google's sidebar. The 2007 print version of the "Britannica" has 4,411 contributors, many eminent in their fields, such as Nobel laureate economist Milton Friedman, astronomer Carl Sagan, and surgeon Michael DeBakey. Roughly a quarter of the contributors are deceased, some as long ago as 1947 (Alfred North Whitehead), while another quarter are retired or emeritus. Most (approximately 98%) contribute to only