Though I was buying a used textbook, I didn't expect the pages will be photocopied. I would have returned it if not for the price I bought it. The pictures of the UNIX dialog box in the text book are not visible because it has a black background and the writing is white and crooked. I have to stain my eyes to see the commands that was typed in. It would have been better if I even got an international edition, so I will know that I paid for what I got.