Britannica: The complete Encyclopedia Britannica and free. Selected articles from more than 70 of the world's top magazines including Newsweek, Discover, and The Economist.
Columbia Encyclopedia: Site contains over 51,000 entries with more than 80,000 hypertext cross-references.
The Concise Columbia Electronic Encyclopedia: More than 14,000 articles, third Edition.
MusicWeb Encyclopedia of Popular Music: Approxiametly 4,000 entries of musicians and songwriters. The types of music found are Jazz, Blues, Rhythm & Blues, Country, Rock 'n' Roll and more.