In other cases, such as our initial publication of the Linux Network Administrator's Guide, sales were reduced because other companies republished some or all of the book at lower cost, which they could do because they had no development costs or royalties. However, over time this problem abated, because the fact that those publishers were not adding value was recognized by the target audience, and eventually marginalized their products. I see many parallels between the work of free software authors and the work of scientists. In most cases, both are more interested in making sure their work is disseminated than in maximizing their return from it. In most cases, the target reader is a peer of the author.
Publishing is designed to enhance reputation as well as to spread the word.
Publishers must be careful to keep prices fair, lest they be seen as taking advantage of the goodwill of their authors, gouging the very customers who also produce their content. In this kind of environment, you have to ask about the role of the publisher as middleman. In the early days of the World Wide Web, the rhetoric was that anyone could be a publisher. After all, with cheap, ubiquitous web servers, the cost of printing and inventory was minimized. There was a great deal of talk of 'disintermediation'.