From Reading

Active Textbook is a free online authoring tool that can turn your vision into reality by creating your own version of an existing PDF with a dynamic touch!

• Active Textbook grabs everything from the source document (original table of contents, hyperlinks, etc.), and adds an additional layer that allows users to add interactive elements on top of the PDF file.
• Teachers/authors can invite students/readers to personalize their publications on their own, without affecting the original file (only visible to them).

Interactive elements such as:

• YouTube, animated pictures, audio and video clips
• Web links, bookmarks, custom TOC
• Uploading external files of any type
• Custom widgets (using HTML Markups and JavaScript)
• Customized quizzes, surveys, and feedbacks using multimedia
• Discussing materials online and built-in dictionary and many more