You can assign security profiles to HTML pages and PDF documents of your ebook or publication.
A security profile will determine whether a page may be accessed (given some conditions) and what end users are allowed to do when viewing this page.
For each security profile you create, you can manage user rights differently; thus, you can decide to leave all rights for the first pages and limit some actions for the others. You can:
By default, ebooks do not have the "Show source code" menu command in their context menu, so end users cannot access the source code of your HTML pages.
You can also lock the pages you want and define conditions to fulfill so that the end user unlock them (password to enter, etc...).
For instance, create demo or trial ebooks and have locked specific pages with a password, which forces end users to buy the ebook in order to access the remaining pages.