Britannica(TM) Free Online Encyclopedia

Britannica(TM) Free Online Encyclopedia: "The Eleventh Edition filled 29 volumes and contains over 44 million words. It contains over 40,000 articles written by over 1,500 authors within their various fields of expertise. What was particularly remarkable was that many of the entries were written by the most famous people of the age. Henry Ford, for example, wrote the article on mass production. As such, it was considered to represent the sum of human knowledge at the beginning of the 20th Century."

Their OCR is obviously on the fritz, with occasional missing chunks and strange characters, but it's still cool.

And out of copyright too - use it as you will.