Macropædia
The Macropædia was introduced in the 15th edition of the Encyclopædia Britannica in 1974 with 19 book having 4,207 articles. In 1985, these articles were combined and made smaller into 17 books with about 700 articles, which can be as short as 2 pages, and as long as 310 pages. The longest article, on the United States, was from the combining of the 50 articles on each state.