I just bought the pre-release ebook of "High Performance Responsive Webdesign" for about 11€. It's ok that it is a raw version, that's what I expected, but the PDF-file contains only 48 pages instead of 250. I think this is a bit short, even for a pre-release book ;)
Could it be that this is a false PDF-file?
That is one of our Early Release books, which means you have early access as the book is being written and released. You will also receive a copy of the completed book once it's done, which is currently scheduled for September. You can read more about our Early Release program at http://shop.oreilly.com/category/earl....
Let us know if you have further questions.