I believe that, as a software documentation publisher, O'Reilly and Associates should release its (e)books under free licenses, free as in freedom, not as in beer. This means that people will be able to use, redistribute, modify, and distribute modified copies of, the works so that they can fit implementations that are different from the original, which is the case with large amounts of software now.
It makes absolutely no sense that people should have to use nonfree documentation for free software. I mean, that isn't right at all! Sure, you can sell it (_for development reasons_), but that doesn't mean you have to put restrictions on it. Richard Stallman has expressly criticized the company for its practices. Trust me, the whole world of computing will become better if O'Reilly Media releases its works free.