Hmmm, hard question to answer - I guess you'd have to ask the people at Apress. They asked me if I wanted it to be available for free when it was just about out of print. I figured it was a good way to reach more readers and it's not like it was a huge money-maker to begin with! I imagine they look at it as a way to gain some good-will from the community and hopefully turn a bad situation (the book wasn't a huge success financially) into something good.