If I upload the entire book, is it secure that only x amount of pages could be downloaded?
Yes. After uploading the book, you can define which pages can be shown. You can even define pages that are not continuous. For example, you can ask that pages 1 to 10 and pages 30 to 70 be shown. You can change the pages being displayed at any time. Further, talking about security, people who look at your book cannot copy the pages of your book as the book pages are converted into individual images and streamed like a YouTube video.
