[1] Although published online in digital form for a number of years, World Book is currently the only American encyclopedia which also still provides a print edition.

[2] The encyclopedia is designed to cover major areas of knowledge uniformly, but it shows particular strength in scientific, technical, historical and medical subjects.

World Book was founded in Chicago by publishers J. H. Hansen and John Bellow, who realized that existing encyclopedias were off-putting to readers.

"As a rule," wrote O'Shea, the founding editor, in the preface of that 1st edition, "encyclopedias are apt to be quite formal and technical.

The new owners created an editorial board to help make sure the entries were aligned with what students studied, from kindergarten to high school.

But as sales plunged in the 1990s, World Book's results were no longer broken out in Berkshire Hathaway financial reports.

Starting in the 2000s, the popularity of World Book declined, which caused the company to focus on its digital content and sales to academic institutions alongside children's trade publications.

[6] Unlike the way most other encyclopedias were printed, World Book has traditionally been published in variously sized volumes, depending on the letter of the alphabet.

World Book editors lay out major articles distinctly, often starting them on a page of their own, perhaps with a two-column heading.

The online version contains links to current web sites and magazine articles, a news section, and video samples.

Electronic editions contained the entire text of the 22-volume World Book Encyclopedia, plus illustrations, video clips, 3D panoramic views, and sounds.

[14] This edition had some Mac-only features, including a more intuitive user interface, Sticky Notes sharing via Bonjour technology, a Trivia Challenge game, a collection of editor-approved webcams, Notepad, speech capabilities and "This Day in History", "Media Showcase" and "Librarian" widgets.

Since November 2007, both the Windows and Mac electronic editions of World Book Encyclopedia have been developed and published by Software MacKiev.