Recently, I was looking for some books on developing desktop applications for Ubuntu. It seemed that Packt Publishing had the most recent titles, which was one of the criteria I was using for selecting the books. However, I noticed that many of them were available as E-books for $5, compared to a hard copy price of $50 or more. After my searching, I then saw numerous Packt ads highlighting the $5 price. How can they (or their authors) be making any money at that price? To me, this removes incentive to spend the effort to create a book of 300 pages or more to sell for $5 a copy. Am I missing something here?