Eh, so many hopes are taken in digital textbooks!
But it is not easy to make a digital textbook.
The real digital textbook really must try as much as possible to replace a live teacher, and it is not easy.

Digital textbook must primarily be:

• Customizable to student by:
• Time and place of learning,
• Speed of learning,
• Degree of gouging in detail,
• Methods of learning,
• Monitor the progress of students (check the acquired knowledge and skills),
• Provide feedback on progress and suggest course of learning,
• Memorize and compare students and give feedback to textbook author for improvement.