General Reference: Encyclopedias

Columbia Encyclopedia
Hosted by bartleby.com, this site contains the complete text of the 6th edition (2001) of the Columbia Encyclopedia.

encyclopedia.com
Encyclopedia.com aggregates more than 100 sources, including encyclopedias, dictionaries, and thesauruses with facts, definitions, biographies, synonyms, pronunciation keys, word origins, and abbreviations.

Wikipedia
Claiming to be the Internet's largest free reference Web site, Wikipedia boasts several million articles written and edited by contributers from around the world. Wikipedia users should beware that "newer articles may still contain significant misinformation, unencyclopedic content, or vandalism."