Offers the 11th Edition Encyclopedia Britannica which is now in the public domain. All articles are searchable and alphabetized.

Online publication of the Columbia Encyclopedia, Sixth Edition.

Electronic encyclopedia with its own content as well as over 10,000 links to the best reference sites on the Internet.

Provides complete text of Encyclopaedia Britannica with search capabilities, related links, and multimedia enhancements. Free trial.

Browsable full text of the 11th edition.

Thousands of categorized entries of trivia - an invaluable resource for answer seekers.

Links to on-line Smithsonian resources and answers to frequently asked questions from A to Z.

Free resource offers more than 50,000 concise articles.

Portal/concise encyclopedia offers fun activities for learning and exercising the mind. Daily articles introduce new topics in the arts, humanities, science, and technology, and provide links to related sites.

An encyclopedia composed of information available on the Internet. MacroReference contains references to large areas of knowledge, FAQs where available, and pointers to relevant areas of the MicroReference. MicroReference contains short bits of information and references to specific subjects.

Possible to conduct research using a database of reliable sources.

Articles explain how hundreds of things work, from elements of the human body to space-age technology.

Free online encyclopedia that allows users to submit their own articles for inclusion in its database.

Reference source with several hypertext linked entries covering a broad variety of subjects.

User edited encyclopedia based on Wiki software. Contains articles, information on editing, and a list of differences between this encyclopedia and Wikipedia.

A free encyclopedia built collaboratively using Wiki software. (GNU Free Documentation License).

Publisher site promoting sales of bound copies and offering link to online version.

Online version of the complete reference work along with dictionary, atlas, links, magazines, historical documents, audio, video, images, and 3D photographs. Requires free temporary registration with option to buy continued access.