From the Wikipedia entry:
Baen Books was founded in 1983 out of a negotiated agreement between Jim Baen and Simon & Schuster. Simon & Schuster was undergoing massive reorganization and wanted to hire Jim Baen to head up and revitalize its science fiction line of its Pocket Books division. Jim Baen, with financial backing from some friends, counter-offered with a proposal to start up a new company named Baen Books and provide Simon & Schuster with a SF line to distribute instead.
Baen Books is "a science fiction and fantasy publishing house that emphasizes space opera, hard science fiction, military science fiction, and fantasy." And they offer up some books online for free.
There's a good explanation of why at the site from "First Librarian" Eric Flint, but here's the gist:
Baen Books is now making available — for free — a number of its titles in electronic format. We're calling it the Baen Free Library. Anyone who wishes can read these titles online — no conditions, no strings attached. (Later we may ask for an extremely simple, name & email only, registration. ) Or, if you prefer, you can download the books in one of several formats. Again, with no conditions or strings attached. (URLs to sites which offer the readers for these format are also listed. )
Why are we doing this? Well, for two reasons.
The first is what you might call a "matter of principle."
Earlier, I mentioned "two reasons" we were doing this, and stated that the first was what you might call a demonstration of principle. What's the second?
Common sense, applied to the practical reality of commercial publishing. Or, if you prefer, the care and feeding of authors and publishers. Or, if you insist on a single word, profit.
Effectively, the "word of mouth" advertising that would come from the result of sharing some works for free online would be ten times more effective than paid advertising, and thus the authors as well as publisher would benefit.
I like that idea.
For more information on the reasoning and justification behind the Baen Free Library, check out Eric's explanation.
And while you're there, "check out" a few books for your own personal library & enjoyment.
Hat-tip to Becca of Opinions Unrestrained, a Delphi forum.