World Book Encyclopedia Information

World Book Encyclopedia is, according to its publisher in the United States, "the number-one selling print encyclopedia in the world." It is based in Chicago, Illinois. The first edition (1917) contained eight volumes. New editions have since appeared every year except 1920, 1924, and 1932, with major revisions in 1929 (13 volumes), 1947 (18,000 illustrations), 1960 (20 volumes), and 1988.

World Book, Inc., is a subsidiary of the Scott Fetzer Company, which is in turn a Berkshire Hathaway subsidiary.

Over the years, the World Book has been characterized by its populist design. Unlike most other encyclopedias, it has traditionally published in nonuniform volumes sized to match the letters of the alphabet. Although most volumes cover exactly one letter completely, each letter with exceptionally many entries ("C" and "S") is divided between two volumes, while adjacent letters with relatively few entries ("J"–"K", "N"–"O", "Q"–"R", "U"–"V", and "W"–"Z") share a volume. World Book editors lay out major articles distinctly, often starting them on a page of their own, perhaps with a two-column heading. Though not called a "children's" encyclopedia, it is marketed as a "family" encyclopedia for readers above 15 years of age. It recognizes that one of the primary uses of general-purpose encyclopedias is children's work on school reports. For instance, every article for a U.S. state has a box giving information such as the official state bird and tree, and many science articles have instructions or suggestions for science projects. Many articles also offer suggestions for additional reading.

It claims to be the most up-to-date encyclopedia sold, thirty-three percent of its pages being revised each year. Illustrations account for about one third of the layout, and some eighty percent are in color. Its cross-references are very extensive as well, and an exhaustive (more than 150,000 entries) analytical index ensures easy access to the contents of the set.