How Stuff Works

Articles explain how hundreds of things work, from elements of the human body to space-age technology.
http://www.howstuffworks.com/

Encyclopaedia Britannica Online

Provides complete text of Encyclopaedia Britannica with search capabilities, related links, and multimedia enhancements. Free trial.
http://www.eb.com/

World Book Encyclopedia

Publisher site promoting sales of bound copies and offering link to online version.
http://www.worldbook.com/

EncycloZine

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.
http://EncycloZine.com/

The Probert Encyclopaedia

Reference source with several hypertext linked entries covering a broad variety of subjects.
http://www.probert-encyclopaedia.co.uk/

Encyberpedia

Electronic encyclopedia with its own content as well as over 10,000 links to the best reference sites on the Internet.
http://www.encyberpedia.com/cyberlinks/links/index.html

Informationsphere.com

Free online encyclopedia that allows users to submit their own articles for inclusion in its database.
http://www.informationsphere.com/

Encyclopedia FunTrivia

Thousands of categorized entries of trivia - an invaluable resource for answer seekers.
http://www.funtrivia.com/trivia.html

Encyclopedia Smithsonian

Links to on-line Smithsonian resources and answers to frequently asked questions from A to Z.
http://www.si.edu/resource/faq/start.htm

Bartleby.com

Online publication of the Columbia Encyclopedia, Sixth Edition.
http://www.bartleby.com/65

The LoveToKnow Free Online Encyclopedia

Browsable. Based on the eleventh edition of the Encyclopedia Britannica, first published in 1911.
http://www.1911encyclopedia.org/

Encyclopedia.com from Electric Library

Free resource offers more than 50,000 concise articles.
http://www.encyclopedia.com/

Free Internet Encyclopedia

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 informatio
http://www.cam-info.net/enc.html

Wikipedia

A free encyclopedia built collaboratively using Wiki software. (GNU Free Documentation License).
http://en.wikipedia.org

Wikinfo

User edited encyclopedia based on Wiki software. Contains articles, information on editing, and a list of differences between this encyclopedia and Wikipedia.
http://www.wikinfo.org/

World Book Encyclopedia

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.
http://www.worldbookonline.com/

HighBeam Library Research

Possible to conduct research using a database of reliable sources.
http://www.highbeam.com/library/

1911 Encyclopedia Britannica

Offers the 11th Edition Encyclopedia Britannica which is now in the public domain. All articles are searchable and alphabetized.
http://encyclopedia.jrank.org/